100+ Free ABD Mohs Surgery Practice Questions

Pass your American Board of Dermatology Micrographic Dermatologic Surgery (MDS) Subspecialty Certification exam on the first try — instant access, no signup required.

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Question 1

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What is the defining feature of Mohs micrographic surgery that distinguishes it from standard surgical excision?

Use of horizontal (en face) frozen sections allowing 100% evaluation of the peripheral and deep margins

Use of vertical (bread-loaf) sections with sampling of every 4 mm

Removal of a 1-cm margin of clinically normal skin

Intraoperative use of wide-field radiation therapy

to track

2026 Statistics

Key Facts: ABD Mohs Surgery Exam

84%

First-Attempt Pass Rate (Oct 2025)

ABD 2025

Sept 23, 2026

2026 Exam Date

ABD 2026

MSDO

ACGME Fellowship Required (2026+)

ABD Policy

2019-2020

ABMS Subspecialty Approval Year

ABD/ABMS

2012 AUC

Appropriate Use Criteria

AAD/ASDS/ACMS/ASMS

Pearson VUE

Test Center Delivery

ABD 2026

The ABD MDS subspecialty exam is the ABMS-recognized board certification for Mohs surgeons. The 2026 exam is scheduled for Wednesday, September 23, 2026 at Pearson VUE test centers, with applications opening in April. The exam is criterion-based — no pre-set pass rate — with a 2025 first-attempt pass rate of 84% (301 of ~358 candidates certified). Beginning with the 2026 administration, all candidates must complete an ACGME-accredited Micrographic Surgery and Dermatologic Oncology (MSDO) fellowship; the practice pathway (grandfathering) closed with the 2025 exam. Question content includes single-best-answer multiple-choice items plus Virtual Dermatopathology (VDP) slide interpretation cases covering Mohs technique, 2012 AUC, NMSC staging, reconstruction, and advanced oncology (hedgehog inhibitors, cemiplimab, adjuvant radiotherapy).

Sample ABD Mohs Surgery Practice Questions

Try these sample questions to test your ABD Mohs Surgery exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1What is the defining feature of Mohs micrographic surgery that distinguishes it from standard surgical excision?

A.Use of horizontal (en face) frozen sections allowing 100% evaluation of the peripheral and deep margins

B.Use of vertical (bread-loaf) sections with sampling of every 4 mm

C.Removal of a 1-cm margin of clinically normal skin

D.Intraoperative use of wide-field radiation therapy

Explanation: Mohs micrographic surgery uniquely employs horizontal (en face) frozen sections that evaluate 100% of the peripheral and deep surgical margins in a single histologic plane. In contrast, standard vertical (bread-loaf) sectioning samples only a small fraction of the total margin, potentially missing tumor extensions. This complete margin assessment is the defining feature that gives Mohs its very high cure rates for NMSC.

2Which of the following best describes the fresh-tissue Mohs technique developed by Frederic Mohs and later refined?

A.Tissue is processed as fresh frozen horizontal sections without chemical fixation

B.Tissue is fixed with zinc chloride paste prior to excision

C.Tissue is fixed in formalin for 24 hours before sectioning

D.Tissue is sectioned vertically in paraffin blocks

Explanation: Fresh-tissue Mohs, refined from Frederic Mohs' original fixed-tissue technique, uses frozen sections of fresh (unfixed) tissue processed horizontally. The original fixed-tissue Mohs required application of zinc chloride paste the day before surgery to fix the tissue in situ. Fresh-tissue Mohs is now the standard because it eliminates the painful chemical fixation step and permits same-day reconstruction.

3When preparing a Mohs specimen, a surgeon colors the 12 o'clock edge with red dye and the 3 o'clock edge with blue dye. What is the primary purpose of this tissue inking step?

A.To maintain precise spatial orientation of the specimen relative to the patient for mapping residual tumor

B.To aid in fixation of the tissue

C.To highlight tumor cells under the microscope

D.To sterilize the specimen

Explanation: Tissue dye (inking) preserves the spatial orientation of the Mohs specimen during processing so that any residual tumor seen on the horizontal frozen section can be precisely mapped back to the corresponding clock-hour position on the patient. Without this orientation, the surgeon cannot know where to take an additional (focused) stage. Red-12 and blue-3 is one common convention, though each lab has its own standard.

4According to the 2012 Appropriate Use Criteria (AUC) for Mohs surgery, which of the following basal cell carcinomas is MOST appropriate for Mohs surgery?

A.A 0.8 cm nodular BCC on the nasal ala in a healthy adult

B.A 0.4 cm nodular BCC on the mid-back in a healthy adult

C.A 0.5 cm superficial BCC on the lateral thigh

D.A 0.3 cm nodular BCC on the shoulder

Explanation: The 2012 AUC rates Mohs as appropriate for any BCC on area H (the 'mask area' of the face — central face, eyelids, nose, lips, chin, ears, etc.) regardless of size, including a 0.8 cm nodular BCC on the nasal ala. BCCs on the trunk or extremities generally require more stringent size or histologic criteria (e.g., ≥2 cm or aggressive subtype) to meet appropriateness. Nasal ala is within H-zone where Mohs is strongly supported.

5Which of the following is classified as an 'aggressive' (high-risk) histologic subtype of basal cell carcinoma in the AUC?

A.Infiltrative / morpheaform

B.Nodular

C.Superficial

D.Pigmented

Explanation: The aggressive histologic BCC subtypes recognized by the AUC include infiltrative, morpheaform (sclerosing), micronodular, and basosquamous. Nodular and superficial BCCs are considered non-aggressive histologic patterns. Infiltrative and morpheaform BCCs have indistinct borders, finger-like extensions, and significantly higher subclinical tumor extension — making Mohs the preferred treatment regardless of size in most locations.

6According to the Brigham and Women's Hospital T staging system for cutaneous squamous cell carcinoma, a tumor with 2 risk factors is classified as:

A.T2b

B.T1

C.T2a

D.T3

Explanation: The Brigham T staging for cSCC uses four risk factors: (1) tumor diameter ≥2 cm, (2) invasion beyond subcutaneous fat or depth ≥6 mm (not including parakeratosis/crust), (3) perineural invasion of nerves ≥0.1 mm in diameter, and (4) poor differentiation. T1 = 0 risk factors, T2a = 1 risk factor, T2b = 2-3 risk factors, T3 = 4 risk factors OR bone invasion. T2b carries substantially higher metastatic risk than T2a.

7Which of the following is the MOST significant predictor of high metastatic risk in cutaneous squamous cell carcinoma?

A.Perineural invasion of a large-caliber nerve (≥0.1 mm in diameter)

B.Tumor location on the lip vermilion

C.Pigmented epidermal invasion

D.Focal spongiosis on biopsy

Explanation: Perineural invasion (PNI) of a large-caliber nerve (≥0.1 mm in diameter) is a major high-risk feature and an independent Brigham T risk factor. It confers markedly higher local recurrence, regional metastasis, and disease-specific death. PNI of small-caliber (<0.1 mm) nerves is less prognostically significant. Large-caliber PNI should trigger MRI evaluation for named-nerve involvement and consideration of adjuvant radiotherapy.

8The maximum recommended dose of plain 1% lidocaine in a healthy 70 kg adult is approximately:

A.315 mg (4.5 mg/kg)

B.700 mg (10 mg/kg)

C.140 mg (2 mg/kg)

D.1000 mg (~14 mg/kg)

Explanation: The maximum dose of plain lidocaine is 4.5 mg/kg (some references cite up to 5 mg/kg). For a 70 kg adult, this is approximately 315 mg, or about 31.5 mL of 1% lidocaine. With epinephrine 1:100,000 or 1:200,000, the maximum dose increases to 7 mg/kg (~490 mg for a 70 kg adult) because epinephrine-induced vasoconstriction slows systemic absorption.

9Buffering 1% lidocaine with sodium bicarbonate 8.4% in a 9:1 ratio accomplishes which of the following?

A.Reduces injection pain by raising the pH closer to physiologic levels

B.Prolongs the duration of anesthesia

C.Increases the peak plasma concentration

D.Activates the drug from a prodrug state

Explanation: Lidocaine is supplied at an acidic pH (~6.0 for plain; ~4.0 with epinephrine) which stings on injection. Buffering with sodium bicarbonate 8.4% in a 9:1 ratio (9 mL lidocaine + 1 mL bicarb) raises the pH closer to physiologic (~7.4), substantially reducing injection pain. Buffering does not prolong duration and slightly reduces shelf life (use within ~1 week refrigerated).

10Which nerve provides sensory innervation to the lower eyelid, lateral nose, and upper lip?

A.Infraorbital nerve (V2 branch)

B.Supraorbital nerve (V1 branch)

C.Mental nerve (V3 branch)

D.Great auricular nerve (C2-3)

Explanation: The infraorbital nerve is a branch of the maxillary division (V2) of the trigeminal nerve and provides sensation to the lower eyelid, lateral nasal side, medial cheek, and upper lip. It exits via the infraorbital foramen roughly 1 cm below the orbital rim in the midpupillary line. An infraorbital nerve block is useful for Mohs reconstruction of the nasal ala, lateral nose, and upper lip.

About the ABD Mohs Surgery Exam

The ABD Micrographic Dermatologic Surgery (MDS) subspecialty certification exam recognizes dermatologists with advanced expertise in Mohs micrographic surgery and dermatologic oncology. Approved as an ABMS subspecialty in 2019-2020, the MDS exam covers Mohs technique (100% margin assessment via horizontal frozen sections), cutaneous oncology (NMSC high-risk features, Brigham T staging, AUC), reconstruction (flaps, grafts, secondary intention), anatomy and anesthesia, complications, and advanced dermatologic oncology. Beginning with the 2026 exam, all candidates must complete an ACGME-accredited Micrographic Surgery and Dermatologic Oncology (MSDO) fellowship.

Questions

100 scored questions

Time Limit

Full-day computer-based exam (~7-8 hours on-site including breaks)

Passing Score

Criterion-referenced scaled passing score (no pre-set pass rate)

Exam Fee

~$2,400-$2,800 (ABD subspecialty — verify current year) (American Board of Dermatology (ABD))

ABD Mohs Surgery Exam Content Outline

25%

Mohs Technique & Slide Interpretation

Fresh-tissue Mohs with 100% margin control, horizontal frozen sections, flag mapping, tissue dye orientation, reading frozen section slides, fresh vs fixed-tissue Mohs

20%

Cutaneous Oncology & AUC

2012 AUC for Mohs (BCC/SCC/MIS), NMSC high-risk features, Brigham T staging cSCC, BCC aggressive subtypes (infiltrative/morpheaform/basosquamous), AJCC staging

20%

Reconstruction: Flaps, Grafts, Secondary Intention

Primary closure along RSTL, FTSG/STSG, advancement/rotation/transposition flaps, bilobed for nasal tip, nasolabial for ala, paramedian forehead, rhombic (Limberg/Dufourmentel)

15%

Anatomy, Anesthesia & Hemostasis

Facial sensory/motor nerves (supraorbital, infraorbital, mental, frontal branch, marginal mandibular), lidocaine max dose 4.5/7 mg/kg, buffering, aluminum chloride, electrocautery

10%

Complications & Peri-Operative Care

Flap necrosis (venous vs arterial), hematoma, infection, nerve injury, anticoagulation management, pacemaker/ICD, keloid and hypertrophic scarring

10%

Advanced Dermatologic Oncology

SLNB for Merkel/high-risk cSCC, adjuvant RT for large-caliber PNI, MRI for named-nerve PNI, vismodegib/sonidegib (BCC), cemiplimab (cSCC), multidisciplinary care

How to Pass the ABD Mohs Surgery Exam

What You Need to Know

Passing score: Criterion-referenced scaled passing score (no pre-set pass rate)
Exam length: 100 questions
Time limit: Full-day computer-based exam (~7-8 hours on-site including breaks)
Exam fee: ~$2,400-$2,800 (ABD subspecialty — verify current year)

Keys to Passing

Complete 500+ practice questions
Score 80%+ consistently before scheduling
Focus on highest-weighted sections
Use our AI tutor for tough concepts

ABD Mohs Surgery Study Tips from Top Performers

1Memorize the 2012 AUC decision framework cold: for BCC and SCC, Mohs is appropriate for H-zone locations (central face, eyelids, nose, lips, ears), aggressive histology (infiltrative, morpheaform, micronodular, desmoplastic, spindle cell, poor differentiation), tumors ≥2 cm on trunk/extremities, recurrent tumors, immunocompromised patients, and lesions with perineural invasion

2Know Brigham T staging for cutaneous SCC cold: T1 has 0 risk factors; T2a has 1; T2b has 2-3; T3 has 4 or bone invasion. The four risk factors are tumor diameter ≥2 cm, invasion beyond subcutaneous fat (or ≥6 mm depth), perineural invasion ≥0.1 mm (large-caliber), and poor differentiation. Brigham T2b/T3 carries substantial metastatic risk and may warrant adjuvant therapy

3Master lidocaine dosing: max 4.5 mg/kg for plain lidocaine, 7 mg/kg when combined with epinephrine 1:100,000 or 1:200,000. Always buffer 9 mL lidocaine with 1 mL sodium bicarbonate 8.4% to reduce injection pain. Onset 2-5 min, duration 1-2 hours (longer with epi). Epinephrine is safe in fingers, toes, nose, and ears for healthy patients — the classic dogma is outdated

4For nasal reconstruction, match defect location to flap: nasal tip <1.5 cm = bilobed flap; alar rim = nasolabial interpolation or bilobed; dorsum = dorsal nasal (Rieger) or rhombic; large subunit defects (>1.5 cm tip/ala) = paramedian forehead flap in 2-3 stages. Respect the subunit principle — when >50% of a subunit is removed, resurface the entire subunit

5Know the frontal branch of the facial nerve (Pitanguy line): from 0.5 cm below tragus to 1.5 cm above lateral eyebrow. Injury causes inability to elevate brow. The marginal mandibular branch runs below the mandibular angle and causes asymmetric smile when injured. Avoid deep undermining in these danger zones — stay superficial to the SMAS in the temple and above the platysma at the mandible

6Differentiate flap failure patterns: venous congestion presents early (hours to 24 h) with dusky, edematous, purple flap with brisk capillary refill — release sutures, consider leech therapy. Arterial insufficiency presents with pale, cool flap with sluggish refill — evaluate tension, consider partial release. Full-thickness necrosis appears at 48-72 hours as black eschar — allow demarcation, conservative debridement, delayed reconstruction

7Memorize the drug-tumor matches for advanced NMSC: locally advanced or metastatic BCC = vismodegib (first-line hedgehog inhibitor) or sonidegib; treatment-limiting side effects include muscle cramps, dysgeusia, alopecia. Locally advanced or metastatic cSCC = cemiplimab (PD-1 inhibitor, first-line); pembrolizumab is second-line. For Merkel cell carcinoma = avelumab or pembrolizumab first-line

8Practice VDP (Virtual Dermatopathology) slide interpretation — the exam includes items where you orient a Mohs map, identify tumor at the margin, and make the clinical decision to take another stage. Use sample VDP items on the ABD website and practice reading horizontal frozen sections with known fresh-tissue Mohs maps. Focus on recognizing tumor invading at 12/3/6/9 o'clock positions on the mapping diagram

Frequently Asked Questions

Who is eligible to take the ABD MDS exam in 2026?

Beginning with the 2026 administration, all candidates must complete an ACGME-accredited Micrographic Surgery and Dermatologic Oncology (MSDO) fellowship. Candidates must also hold primary ABD certification in good standing and an active, unrestricted medical license. The practice pathway (grandfathering), which allowed experienced Mohs surgeons without formal fellowship training to sit for the exam, closed permanently with the 2025 administration.

How is the ABD MDS exam structured?

The MDS exam is a full-day computer-based exam at Pearson VUE test centers (approximately 7-8 hours on-site including breaks). It combines single-best-answer multiple-choice questions with Virtual Dermatopathology (VDP) cases that require candidates to interpret Mohs horizontal frozen section slides. The 2026 exam is scheduled for Wednesday, September 23, 2026.

What is the pass rate for the ABD MDS exam?

The October 2025 administration had a first-attempt pass rate of 84% — 301 physicians were certified in Micrographic Dermatologic Surgery. The ABD uses a criterion-referenced scoring model with no pre-set pass rate, meaning all candidates who meet the standard can pass. Historical pass rates have ranged from approximately 80% to 90%.

What does the ABD MDS exam cost?

The ABD does not publicly list a flat fee for the MDS subspecialty exam, but typical ABD subspecialty exam fees range from approximately $2,400 to $2,800. Applicants pay when registering through the ABD diplomate portal. Total preparation cost including review courses (ASDS MDS Exam Review, ACMS resources), textbooks, and travel typically reaches $4,000-$6,000.

What topics are emphasized on the MDS exam?

The exam emphasizes Mohs technique and slide interpretation (~25%), cutaneous oncology and 2012 Appropriate Use Criteria (~20%), reconstruction with flaps and grafts (~20%), anatomy/anesthesia/hemostasis (~15%), complications (~10%), and advanced dermatologic oncology (~10%). High-yield topics include Brigham T staging for cSCC, large-caliber PNI and adjuvant radiotherapy, hedgehog inhibitors for advanced BCC, cemiplimab for advanced cSCC, and flap design geometry.

What is the 2012 Appropriate Use Criteria (AUC) for Mohs surgery?

The 2012 AUC, developed jointly by AAD, ASDS, ACMS, and ASMS, uses a 9-point appropriateness scale across 270 clinical scenarios. It considers tumor type, aggressive histology, anatomic location (H-zone/M-zone/L-zone), size, patient factors (immunosuppression, prior radiation, recurrence), and recurrent versus primary status. Mohs is rated appropriate for BCC and SCC in high-risk locations, aggressive histologic subtypes, recurrent tumors, and lesions in cosmetically sensitive or functionally critical areas. The AUC is highly tested on the MDS exam.

How do I maintain ABD MDS certification?

MDS certification is maintained through ABD CertLink, the longitudinal knowledge assessment platform. Diplomates complete approximately 13 questions per quarter with MDS-specific content integrated into their quarterly assessments. CertLink replaces the traditional 10-year recertification exam and allows continuous learning with immediate rationales. Diplomates must also maintain primary ABD certification and an active unrestricted medical license.

How long should I study for the ABD MDS exam?

Most candidates study 200-400 hours over 6-9 months during or immediately after the MSDO fellowship. Preparation typically combines the ASDS MDS Exam Review Course, ACMS resources, Rohrer's Mohs Surgery textbook, Stalter/Otley Cutaneous Oncology, AUC review, and focused VDP slide practice. Your fellowship clinical and surgical volume is the strongest predictor of first-attempt success.