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ABD Mohs Surgery study materials
ABD Mohs Surgery study resources

ABD Mohs Surgery practice questions

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Question 1Cutaneous Oncology and Tumor Biology

Which cell type of the epidermis is the origin of basal cell carcinoma?

  1. Merkel cells of the basal layer
  2. Langerhans cells of the stratum spinosum
  3. Melanocytes of the basal layer
  4. Keratinocytes of the basal layer Correct answer.

Explanation

Basal cell carcinoma arises from pluripotent keratinocytes of the basal epidermis and hair follicle epithelium. Melanocytes give rise to melanoma, and Merkel cells give rise to Merkel cell carcinoma.

Question 2Cutaneous Oncology and Tumor Biology

Squamous cell carcinoma in situ of the skin, confined to the epidermis, is best termed which of the following?

  1. Leukoplakia
  2. Keratoacanthoma
  3. Actinic keratosis
  4. Bowen disease Correct answer.

Explanation

Bowen disease is full-thickness epidermal atypia without dermal invasion, i.e., squamous cell carcinoma in situ. Actinic keratosis is a partial-thickness precursor lesion, and keratoacanthoma is an invasive squamoproliferative lesion.

Question 3Cutaneous Oncology and Tumor Biology

Which histologic feature is most characteristic of nodular basal cell carcinoma?

  1. Peripheral palisading of basaloid cells Correct answer.
  2. Tumor islands with abundant keratin pearls
  3. Desmoplastic stroma with single-file cells
  4. Numerous atypical melanocytes at the dermoepidermal junction

Explanation

Nodular basal cell carcinoma shows nests of basaloid cells with peripheral palisading and retraction artifact from surrounding mucinous stroma. Keratin pearls and single-file desmoplasia are features of squamous and infiltrative/morpheaform variants respectively.

Question 4Cutaneous Oncology and Tumor Biology

Which subtype of basal cell carcinoma is most often associated with subclinical extension and thus a higher risk of positive margins with standard excision?

  1. Superficial
  2. Pigmented
  3. Nodular
  4. Morpheaform Correct answer.

Explanation

Morpheaform (infiltrative) basal cell carcinoma grows in thin strands through fibrous stroma with poorly defined clinical borders, producing extensive subclinical spread. Nodular, superficial, and pigmented variants generally have more circumscribed margins.

Question 5Cutaneous Oncology and Tumor Biology

Which of the following is the most important etiologic risk factor for cutaneous squamous cell carcinoma of the head and neck?

  1. Cumulative ultraviolet radiation exposure Correct answer.
  2. Human papillomavirus type 6 infection
  3. High dietary folate intake
  4. Chronic hepatitis C infection

Explanation

Cumulative ultraviolet radiation is the dominant environmental cause of cutaneous squamous cell carcinoma, producing characteristic p53 mutations. Hepatitis viruses and low-risk HPV types are not established cutaneous carcinogens.

Question 6Cutaneous Oncology and Tumor Biology

In a patient with a newly diagnosed basal cell carcinoma, which additional cutaneous malignancy is most strongly associated with the same cumulative sun exposure?

  1. Dermatofibrosarcoma protuberans
  2. Squamous cell carcinoma Correct answer.
  3. Sebaceous carcinoma of the eyelid
  4. Mycosis fungoides

Explanation

Basal cell carcinoma and squamous cell carcinoma share cumulative ultraviolet exposure as their principal driver and frequently co-occur in the same patient. Dermatofibrosarcoma, mycosis fungoides, and most sebaceous carcinomas have unrelated pathogenesis.

Question 7Cutaneous Oncology and Tumor Biology

Which of the following best describes the concept of field cancerization relevant to Mohs surgery?

  1. Diffuse genetic alteration of sun-damaged skin predisposes to multifocal tumors Correct answer.
  2. A benign lesion mimics malignancy on clinical examination
  3. Tumor cells spread along perineural sheaths beyond visible margins
  4. A single tumor metastasizes to distant skin through lymphatic channels

Explanation

Field cancerization refers to broad, chronically sun-damaged skin bearing multiple genetically altered clones, which explains multifocal and recurrent tumors. Perineural spread and metastasis are distinct mechanisms of tumor extension.

Question 8Cutaneous Oncology and Tumor Biology

Which tumor most commonly arises from the skin of the external ear and is known for aggressive local behavior and high recurrence after simple excision?

  1. Seborrheic keratosis
  2. Squamous cell carcinoma Correct answer.
  3. Basal cell carcinoma of the trunk
  4. Dermatofibroma

Explanation

Squamous cell carcinoma of the ear arises in a thin-skinned, high-risk anatomic site and carries elevated rates of recurrence and metastasis. Basal cell carcinoma is less common on the ear and dermatofibroma and seborrheic keratosis are benign.

Question 9Cutaneous Oncology and Tumor Biology

Which histologic finding in a squamous cell carcinoma most strongly predicts an increased risk of local recurrence and warrants Mohs micrographic surgery?

  1. Presence of a granular layer
  2. Abundant parakeratosis
  3. Perineural invasion Correct answer.
  4. Mild stromal solar elastosis

Explanation

Perineural invasion allows tumor to track along nerve sheaths far beyond clinically apparent margins, making complete margin control essential. Parakeratosis, solar elastosis, and a granular layer are nonspecific or normal findings.

Question 10Cutaneous Oncology and Tumor Biology

In the tumor-node-metastasis staging of cutaneous squamous cell carcinoma, which feature is considered a high-risk factor for upstaging?

  1. Tumor diameter greater than 2 cm Correct answer.
  2. Well-differentiated histology
  3. Tumor diameter less than 1 cm
  4. Location on the trunk

Explanation

Tumor diameter greater than 2 cm is a recognized high-risk feature in cutaneous squamous cell carcinoma staging. Small size, well-differentiated histology, and truncal location are lower-risk characteristics.

Question 11Cutaneous Oncology and Tumor Biology

Which of the following best characterizes the biologic behavior of melanoma compared with basal cell carcinoma?

  1. Melanoma is uniformly chemosensitive
  2. Melanoma arises only from chronically sun-exposed skin
  3. Melanoma is exclusively locally destructive and does not metastasize
  4. Melanoma has a greater propensity for early lymphatic and hematogenous metastasis Correct answer.

Explanation

Melanoma metastasizes early via lymphatics and blood, whereas basal cell carcinoma is locally destructive and rarely metastasizes. Melanoma also arises on acral and mucosal sites and is not uniformly chemosensitive.

Question 12Cutaneous Oncology and Tumor Biology

Which of the following is the most important prognostic factor in primary cutaneous melanoma?

  1. Patient's hair color
  2. Presence of associated nevus
  3. Breslow tumor thickness Correct answer.
  4. Clark level of invasion

Explanation

Breslow thickness, measured in millimeters from the granular layer to the deepest tumor cell, is the strongest predictor of survival and drives sentinel node discussion. Clark level and associated nevus have lesser or no independent prognostic value.

Question 13Cutaneous Oncology and Tumor Biology

A 62-year-old man has a 1.2 mm Breslow-thickness melanoma on the back with no clinical nodal disease. Which staging procedure is most appropriate to evaluate the regional basin?

  1. Sentinel lymph node biopsy Correct answer.
  2. Complete cervical lymph node dissection
  3. Bone marrow biopsy
  4. Positron emission tomography of the whole body

Explanation

Sentinel lymph node biopsy is offered for melanomas with Breslow thickness above approximately 0.8 to 1.0 mm to stage the regional basin. Complete dissection, whole-body PET, and marrow biopsy are not first-line staging for clinically node-negative disease.

Question 14Cutaneous Oncology and Tumor Biology

Which of the following best describes lentigo maligna?

  1. Benign junctional nevus of the palm
  2. Metastatic melanoma to the skin
  3. Melanoma in situ on chronically sun-damaged skin Correct answer.
  4. Nodular invasive melanoma on the trunk

Explanation

Lentigo maligna is melanoma in situ arising on severely sun-damaged skin, typically the face of older adults, and may progress to lentigo maligna melanoma. It is not a benign nevus or a metastatic deposit.

Question 15Cutaneous Oncology and Tumor Biology

Why is Mohs micrographic surgery particularly well suited to lentigo maligna on the face?

  1. It eliminates the need for any histologic interpretation
  2. It prevents all future melanomas in the field
  3. It allows complete margin assessment of a tumor with ill-defined subclinical extension Correct answer.
  4. It guarantees a narrower final defect than any other technique

Explanation

Lentigo maligna has poorly defined clinical margins with atypical melanocytes extending along adnexa, so complete peripheral and deep margin evaluation by Mohs improves clearance while sparing tissue. Mohs still requires histologic interpretation and does not prevent new field tumors.

Question 16Cutaneous Oncology and Tumor Biology

Which of the following is the most common site of metastasis from cutaneous squamous cell carcinoma of the head and neck?

  1. Cervical lymph nodes Correct answer.
  2. Lung parenchyma
  3. Liver
  4. Bone

Explanation

Cutaneous squamous cell carcinoma of the head and neck spreads first to regional cervical lymph nodes. Distant organ involvement is uncommon and typically follows nodal disease.

Question 17Cutaneous Oncology and Tumor Biology

Which of the following histologic features is characteristic of keratoacanthoma?

  1. Atypical melanocytes in the basal epidermis
  2. Crateriform architecture with a central keratin plug Correct answer.
  3. Nests of basaloid cells with peripheral palisading
  4. Diffuse dermal mucin without epithelial proliferation

Explanation

Keratoacanthoma shows a cup-shaped, crateriform invagination filled with keratin and well-differentiated squamous epithelium. Basaloid palisading and atypical melanocytes describe basal cell carcinoma and melanoma.

Question 18Cutaneous Oncology and Tumor Biology

A patient with chronic lymphocytic leukemia develops a rapidly enlarging squamous cell carcinoma on the scalp. Which statement best explains the clinical significance of this association?

  1. The tumor will not require margin-controlled excision
  2. Immunosuppression from the disease and its therapy increases tumor aggressiveness and recurrence Correct answer.
  3. The tumor is likely benign because of the hematologic disease
  4. The tumor is unrelated to the leukemia and follows a normal course

Explanation

Chronic lymphocytic leukemia and its treatment produce immunosuppression that is associated with more aggressive squamous cell carcinoma, higher recurrence, and worse outcomes. These tumors warrant careful margin-controlled management.

Question 19Cutaneous Oncology and Tumor Biology

Which of the following best describes the role of PTCH1 mutations in basal cell carcinoma?

  1. Gain of function suppresses Hedgehog signaling
  2. They are diagnostic of melanoma
  3. They are found only in squamous cell carcinoma
  4. Loss of function activates the Hedgehog signaling pathway Correct answer.

Explanation

Inactivating PTCH1 mutations release SMO and constitutively activate Hedgehog signaling, driving basal cell carcinoma growth. This pathway is the target of vismodegib and other Hedgehog inhibitors.

Question 20Cutaneous Oncology and Tumor Biology

Which of the following best explains why basal cell carcinomas of the nose are often treated with Mohs surgery rather than wide local excision?

  1. Wide excision is contraindicated anywhere on the face
  2. Mohs surgery provides no margin control on the nose
  3. Tissue conservation is critical in an anatomically constrained cosmetic unit Correct answer.
  4. Basal cell carcinoma of the nose never recurs

Explanation

The nose has limited tissue reserve and high cosmetic and functional stakes, so Mohs offers complete margin control with maximal tissue preservation. Wide excision is not contraindicated but removes more normal tissue.

Question 21Cutaneous Oncology and Tumor Biology

Which of the following subtypes of basal cell carcinoma is most likely to be mistaken clinically for a scar or a benign fibrotic plaque?

  1. Morpheaform Correct answer.
  2. Nodular
  3. Superficial
  4. Cystic

Explanation

Morpheaform basal cell carcinoma presents as an ill-defined, indurated, scar-like plaque because tumor strands are embedded in dense fibrous stroma. Nodular and cystic variants form discrete nodules, and superficial variants form scaly patches.

Question 22Cutaneous Oncology and Tumor Biology

A biopsy shows atypical squamous cells confined to the lower third of the epidermis with overlying parakeratosis on sun-damaged skin. What is the most likely diagnosis?

  1. Invasive squamous cell carcinoma
  2. Actinic keratosis Correct answer.
  3. Squamous cell carcinoma in situ
  4. Basal cell carcinoma

Explanation

Actinic keratosis shows atypical keratinocytes confined to the lower epidermis, typically with parakeratosis and solar elastosis. Full-thickness atypia would indicate carcinoma in situ, and invasion requires dermal involvement.

Question 23Cutaneous Oncology and Tumor Biology

Which of the following best describes the concept of subclinical extension in cutaneous tumors treated with Mohs surgery?

  1. A tumor's tendency to bleed on contact
  2. The depth of the biopsy specimen
  3. Tumor spread beyond the visible clinical margin that is detected only on microscopic examination Correct answer.
  4. Metastatic spread to regional lymph nodes

Explanation

Subclinical extension refers to tumor that extends beyond the clinically apparent border and can only be found by examining the surgical margin microscopically. This is the rationale for staged margin-controlled excision.

Question 24Cutaneous Oncology and Tumor Biology

Which genetic syndrome is characterized by multiple basal cell carcinomas, jaw cysts, and palmar pits and is caused by PTCH1 mutation?

  1. Li-Fraumeni syndrome
  2. Muir-Torre syndrome
  3. Gorlin syndrome Correct answer.
  4. Xeroderma pigmentosum

Explanation

Gorlin syndrome (nevoid basal cell carcinoma syndrome) results from germline PTCH1 mutations and causes multiple basal cell carcinomas, odontogenic keratocysts, and palmar/plantar pits. Muir-Torre and Li-Fraumeni involve mismatch repair and TP53 defects respectively.

Question 25Cutaneous Oncology and Tumor Biology

Which of the following best explains why melanoma in situ can be challenging to clear with standard excision margins?

  1. Melanoma in situ always metastasizes early
  2. Melanoma in situ is confined strictly to the visible border
  3. Melanoma in situ is resistant to all surgical treatment
  4. Atypical melanocytes may extend along adnexal structures beyond the visible pigment Correct answer.

Explanation

Atypical melanocytes in melanoma in situ can track down hair follicles and eccrine ducts beyond clinically apparent margins, causing incomplete clearance with simple excision. This is why margin-controlled techniques are used for lentigo maligna.

Question 26Cutaneous Oncology and Tumor Biology

Which of the following best describes the primary function of the PTCH1 protein in the absence of Hedgehog ligand?

  1. It inhibits Smoothened and suppresses downstream GLI transcription factors. Correct answer.
  2. It translocates to the nucleus and acts as a coactivator for GLI targets.
  3. It activates Smoothened and promotes GLI-mediated transcription.
  4. It directly phosphorylates GLI proteins, marking them for degradation.

Explanation

PTCH1 is a transmembrane receptor that, without Hedgehog ligand, constitutively inhibits Smoothened. This inhibition prevents activation of the GLI transcription factors and keeps the pathway off.

Question 27Cutaneous Oncology and Tumor Biology

A 70-year-old man has a 2.5 cm squamous cell carcinoma on the dorsal hand that has been present for 2 years. He has no history of organ transplantation or chronic lymphocytic leukemia. According to current staging and risk stratification, which factor most strongly increases his risk for local recurrence and metastasis?

  1. Tumor diameter greater than 2 cm Correct answer.
  2. Anatomical location on the dorsal hand
  3. Duration of tumor growth exceeding 1 year
  4. Male sex

Explanation

In cutaneous SCC, a tumor diameter of 2 cm or greater is a well-established high-risk feature associated with increased local recurrence and metastatic risk. Other high-risk factors include depth, perineural invasion, poor differentiation, and immunosuppression.

Question 28Cutaneous Oncology and Tumor Biology

A 55-year-old woman undergoes Mohs surgery for a biopsy-proven morpheaform basal cell carcinoma on the nasal ala. The tumor measures 1.0 cm. Which feature of this tumor most likely explains the need for Mohs surgery rather than standard excision?

  1. The patient is younger than 60 years, increasing recurrence risk.
  2. The tumor is located on the nasal ala, a high-risk anatomical site.
  3. The tumor size exceeds 2 cm, warranting Mohs.
  4. The morpheaform subtype is associated with extensive subclinical extension. Correct answer.

Explanation

Morpheaform (infiltrative) basal cell carcinoma often has ill-defined clinical borders and extensive subclinical spread, making margin control with Mohs surgery particularly valuable. While the nasal ala is a high-risk site, the histologic subtype is the primary driver of subclinical extension.

Question 29Cutaneous Oncology and Tumor Biology

A 68-year-old man with a history of chronic sun exposure presents with a 1.5 cm pearly papule on the lower eyelid margin. Biopsy shows nodular basal cell carcinoma. Which of the following statements best explains why Mohs micrographic surgery is preferred over standard excision for this tumor?

  1. Standard excision has a higher cure rate for eyelid tumors but is more technically demanding.
  2. Standard excision is contraindicated on the eyelid due to poor vascular supply.
  3. Mohs is preferred because it eliminates the need for reconstructive surgery.
  4. Mohs allows examination of 100% of the surgical margin, reducing recurrence risk while preserving healthy tissue. Correct answer.

Explanation

Mohs micrographic surgery examines the entire peripheral and deep margin, which maximizes cure rates and minimizes tissue removal, an advantage in cosmetically and functionally sensitive areas like the eyelid. Standard excision examines only a small fraction of the margin.

Question 30Cutaneous Oncology and Tumor Biology

A 60-year-old man has a 2.0 cm squamous cell carcinoma on the scalp with perineural invasion of a small dermal nerve. Imaging shows no gross nerve involvement. According to current staging and risk stratification, which of the following best characterizes the impact of perineural invasion on his prognosis?

  1. It is a low-risk feature that does not alter management.
  2. It is a high-risk feature only if the involved nerve is named and at least 0.1 mm in caliber.
  3. It is a high-risk feature that increases the risk of local recurrence and metastasis. Correct answer.
  4. It is a high-risk feature only in tumors larger than 2 cm.

Explanation

Perineural invasion, even of small dermal nerves, is a high-risk feature in cutaneous SCC associated with increased local recurrence and metastatic risk, and it often prompts more aggressive treatment such as Mohs surgery with nerve tracing or adjuvant radiation.

Question 31Mohs Micrographic Surgery Technique and Indications

Which tissue layer must be included in the specimen when performing Mohs micrographic surgery to allow complete margin assessment?

  1. The epidermis and full dermis
  2. The epidermis only
  3. The epidermis, dermis, and a rim of subcutaneous fat Correct answer.
  4. The deep fascia underlying the defect

Explanation

Complete margin assessment requires that the entire specimen, including the deep margin, be flattened and sectioned. Including a rim of subcutaneous fat ensures the deep margin is present in the frozen section. Epidermis and dermis alone leave the deep margin unassessable.

Question 32Mohs Micrographic Surgery Technique and Indications

In Mohs surgery, the excised tissue layer is typically flattened and sectioned so that what percentage of the peripheral and deep margin is examined?

  1. About 50%
  2. About 75%
  3. Essentially 100% Correct answer.
  4. About 25%

Explanation

Mohs micrographic surgery examines essentially the entire peripheral and deep margin by flattening the specimen and cutting horizontal sections. This complete margin control distinguishes it from conventional vertical-section pathology. Partial sampling leaves unexamined margins.

Question 33Mohs Micrographic Surgery Technique and Indications

Which feature most strongly favors Mohs micrographic surgery over wide local excision for a basal cell carcinoma?

  1. A small nodular lesion on the trunk with clear margins
  2. A superficial lesion amenable to curettage
  3. Ill-defined clinical borders in a cosmetically sensitive location Correct answer.
  4. A lesion in a patient who prefers a single-stage procedure

Explanation

Mohs is favored for tumors with ill-defined borders, aggressive histology, or location in tissue-sparing areas such as the face. Tissue conservation with complete margin control is the core advantage. Small well-defined truncal lesions and superficial lesions are often adequately treated by simpler methods.

Question 34Mohs Micrographic Surgery Technique and Indications

The primary reason a Mohs layer is divided and mapped before processing is to:

  1. Reduce the cost of histology
  2. Allow precise anatomic correlation between the tissue map and microscopic findings Correct answer.
  3. Avoid the need for frozen sections
  4. Speed up the embedding process

Explanation

A map with orientation marks allows the surgeon to relate any positive margin on the slide back to the exact location in the wound. This spatial correlation enables targeted re-excision of only the involved area. Mapping is about localization, not cost or speed.

Question 35Mohs Micrographic Surgery Technique and Indications

Which marking method best preserves orientation of a Mohs specimen between the patient and the laboratory?

  1. Storing the specimen at room temperature without a map
  2. Placing the specimen in formalin without marks
  3. Nicking or dye-marking specific edges and correlating them with a drawn map Correct answer.
  4. Cutting the specimen into random fragments

Explanation

Orientation requires a reproducible reference system, typically nicks, sutures, or dyes on defined edges matched to a drawn map. Without such marks, a positive margin cannot be localized. Random fragmentation and informal storage destroy spatial information.

Question 36Mohs Micrographic Surgery Technique and Indications

Which tumor characteristic is a recognized indication for Mohs surgery because of its propensity for subclinical extension?

  1. Solar lentigo
  2. Clear cell acanthoma
  3. Morpheaform basal cell carcinoma Correct answer.
  4. Seborrheic keratosis

Explanation

Morpheaform (morpheic) basal cell carcinoma has ill-defined, infiltrative subclinical extension that is poorly appreciated clinically. Mohs provides complete margin control for such aggressive subtypes. The other lesions listed are benign and not Mohs indications.

Question 37Mohs Micrographic Surgery Technique and Indications

During Mohs surgery, the surgeon personally examines the frozen-section slides primarily to:

  1. Correlate histology with the surgical map and decide on further excision Correct answer.
  2. Determine the need for antibiotics
  3. Bill for pathology services
  4. Confirm the patient's identity

Explanation

The Mohs surgeon interprets the slides in conjunction with the map to identify residual tumor and direct the next stage. This surgeon-performed histologic interpretation is a defining feature of Mohs. Billing, identity, and antibiotic decisions are unrelated to slide interpretation.

Question 38Mohs Micrographic Surgery Technique and Indications

A key advantage of Mohs surgery regarding tissue conservation is that it:

  1. Removes a fixed wide margin regardless of tumor extent
  2. Excises only the tissue needed to reach a clear margin, stage by stage Correct answer.
  3. Always avoids the need for reconstruction
  4. Requires no histologic confirmation of margins

Explanation

Mohs removes tissue incrementally, guided by margin status at each stage, sparing uninvolved tissue. This is especially valuable in cosmetically and functionally sensitive areas. It is not a fixed-margin technique and still requires histologic confirmation.

Question 39Mohs Micrographic Surgery Technique and Indications

A patient has a recurrent basal cell carcinoma at the nasal ala after prior excision. Which management is most appropriate?

  1. Topical imiquimod
  2. Curettage and electrodesiccation
  3. Mohs micrographic surgery Correct answer.
  4. Observation with annual photography

Explanation

Recurrent tumors, particularly in anatomically challenging areas, have unpredictable subclinical spread and are best managed with complete margin control. Mohs is the preferred approach for recurrent basal cell carcinoma in such locations. Destructive or topical therapies cannot confirm margin clearance.

Question 40Mohs Micrographic Surgery Technique and Indications

When a Mohs stage shows tumor at the margin on the slide, the surgeon should next:

  1. Re-excise the entire wound circumferentially at the same depth
  2. Excise additional tissue only from the mapped area of involvement Correct answer.
  3. Observe the defect for healing by secondary intention
  4. Close the defect and refer for radiation

Explanation

The map localizes the positive margin so that additional tissue can be taken precisely from the involved area. This targeted re-excision is the essence of staged Mohs surgery. Circumferential re-excision wastes uninvolved tissue, and observation or closure would leave residual tumor.

Question 41Mohs Micrographic Surgery Technique and Indications

Which specimen-handling step most helps prevent a false-negative margin reading caused by tissue dehydration artifact?

  1. Placing the specimen directly on the cryostat blade
  2. Proper embedding and prompt freezing of the oriented specimen Correct answer.
  3. Cutting sections thicker than 10 micrometers
  4. Immersing the specimen in formalin overnight before freezing

Explanation

Prompt, proper embedding and freezing preserve cellular detail and margin architecture for frozen-section interpretation. Delay and improper handling introduce artifact that can obscure tumor. Thick sections and direct blade contact degrade section quality.

Question 42Mohs Micrographic Surgery Technique and Indications

A Mohs layer is taken from a concave anatomic site such as the nasal ala. To obtain a flat, complete section the technician should:

  1. Section the tissue vertically at the edges
  2. Freeze the tissue in a spherical shape
  3. Relax and flatten the tissue, scoring or dividing it as needed to lie flat Correct answer.
  4. Discard the central portion of the specimen

Explanation

Concave or curved specimens must be relaxed and flattened, sometimes by scoring the base, so the entire margin lies in one plane. This preserves complete margin representation. Discarding tissue or vertical edge sectioning loses margin information.

Question 43Mohs Micrographic Surgery Technique and Indications

Which of the following best describes the concept of the 'debulking' step in Mohs surgery?

  1. Sending tissue for permanent section instead of frozen section
  2. Excising a 5 mm margin around the tumor
  3. Closing the wound before margin confirmation
  4. Removing the visible tumor before taking the first mapped Mohs layer Correct answer.

Explanation

Debulking removes the grossly visible tumor so the subsequent mapped layer represents the true surgical margin. The debulked tissue is generally not used for margin assessment because it is central tumor. It is distinct from a fixed wide margin or permanent sectioning.

Question 44Mohs Micrographic Surgery Technique and Indications

Which lesion is generally the LEAST appropriate candidate for Mohs micrographic surgery?

  1. A large basal cell carcinoma with ill-defined margins on the cheek
  2. A recurrent squamous cell carcinoma on the ear
  3. A small, well-defined superficial basal cell carcinoma on the back Correct answer.
  4. A dermatofibrosarcoma protuberans on the trunk

Explanation

Mohs is reserved for tumors where complete margin control or tissue conservation offers clear advantage. A small, well-defined superficial lesion on the trunk is typically adequately treated with simpler methods. Ill-defined, recurrent, or locally aggressive tumors are stronger Mohs indications.

Question 45Mohs Micrographic Surgery Technique and Indications

Why are frozen sections preferred over permanent sections during Mohs surgery?

  1. Frozen sections require no tissue orientation
  2. Permanent sections cannot be stained
  3. Frozen sections are always more accurate than permanent sections
  4. Frozen sections provide faster results, allowing same-day staged excision Correct answer.

Explanation

Frozen sections can be prepared and interpreted within minutes, enabling same-day staged excision and immediate reconstruction. Permanent sections take longer and would require multiple visits. Frozen sections are not inherently more accurate and still require orientation.

Question 46Mohs Micrographic Surgery Technique and Indications

During a Mohs stage, the surgeon notes inflammation and fibrosis obscuring the margin on the slide. What is the most appropriate action?

  1. Refer the patient for radiation without further excision
  2. Assume the margin is clear and close the defect
  3. Treat the area with topical corticosteroids and recheck in weeks
  4. Obtain additional sections or deeper levels to clarify the margin Correct answer.

Explanation

When artifact or fibrosis obscures margin interpretation, additional sections or deeper levels are needed to resolve the ambiguity. Assuming clearance risks leaving tumor. Deferring to radiation or topical therapy does not confirm margin status.

Question 47Mohs Micrographic Surgery Technique and Indications

Which anatomic location most favors Mohs surgery because of the high value of tissue conservation?

  1. Upper back
  2. Nasal tip Correct answer.
  3. Thigh
  4. Buttock

Explanation

The nasal tip is a cosmetically and functionally critical area where preserving tissue is paramount, making Mohs advantageous. The back, thigh, and buttock have greater tissue redundancy and less aesthetic consequence.

Question 48Mohs Micrographic Surgery Technique and Indications

A Mohs map uses a clock-face orientation with the 12 o'clock position at the superior edge. A positive margin is reported at 3 o'clock on the map. Where should the surgeon take additional tissue?

  1. Central base of the defect
  2. Lateral edge corresponding to 3 o'clock on the map Correct answer.
  3. Inferior edge of the defect
  4. Superior edge of the defect

Explanation

The map's orientation must be consistently translated to the wound. With 12 o'clock superior, 3 o'clock corresponds to the lateral edge. Targeted re-excision follows the mapped location, not arbitrary edges.

Question 49Mohs Micrographic Surgery Technique and Indications

Which statement about the role of the Mohs technician in specimen processing is most accurate?

  1. The technician performs the reconstruction
  2. The technician selects the surgical margin width
  3. The technician independently decides whether margins are clear
  4. The technician embeds and sections the oriented specimen so the surgeon can interpret margins Correct answer.

Explanation

The technician's role is to process the oriented specimen so that complete, interpretable sections reach the surgeon. Margin interpretation and surgical decisions remain with the surgeon. Reconstruction and margin selection are surgical responsibilities.

Question 50Mohs Micrographic Surgery Technique and Indications

A 2 cm nodular basal cell carcinoma on the cheek has been present for years and extends clinically to the periosteum. Which consideration most affects the Mohs plan?

  1. Mohs cannot be used near bone
  2. A single stage will always suffice
  3. Deep margin must include periosteum or bone if involved Correct answer.
  4. Only the epidermis needs to be excised

Explanation

When tumor extends to deep structures, the Mohs layers must include those structures so the deep margin can be assessed. Periosteum or bone may need to be included if involved. Mohs can be used near bone, and multiple stages may be required.