Skin tumours: perineural invasion in squamous cell carcinoma: practice question

A Dermatology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Dermatology · Skin tumours: perineural invasion in squamous cell carcinoma

Sample item

A 70-year-old man has a recurrent cutaneous squamous cell carcinoma of the cheek with numbness and tingling over the lip. Biopsy shows tumour cells tracking around a nerve. How should this histological feature be regarded?

AA reason to reduce surgical marginsBA high-risk feature that increases recurrence and metastasisCA benign incidental findingDA feature seen only in basal cell carcinoma

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

B. A high-risk feature that increases recurrence and metastasis

Perineural invasion, especially of larger nerves, is a high-risk feature of cutaneous squamous cell carcinoma, with higher rates of local recurrence and nodal metastasis. Other high-risk features include thickness, poor differentiation, immunosuppression and recurrence. Such tumours often warrant wider excision or Mohs surgery with adjuvant radiotherapy.

Option by option

A. A reason to reduce surgical margins
Margins are widened rather than reduced in high-risk tumours.
B. A high-risk feature that increases recurrence and metastasis (correct)
Correct. Perineural invasion carries a worse prognosis and justifies more aggressive treatment.
C. A benign incidental finding
Tumour around nerves is not benign, and numbness shows nerve involvement.
D. A feature seen only in basal cell carcinoma
It occurs in squamous cell carcinoma too, and is not exclusive to basal cell carcinoma.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Questions about this Dermatology question

What is the answer to this Dermatology question?

The best answer is B, A high-risk feature that increases recurrence and metastasis. Perineural invasion, especially of larger nerves, is a high-risk feature of cutaneous squamous cell carcinoma, with higher rates of local recurrence and nodal metastasis.

Why is "A reason to reduce surgical margins" not the answer?

Margins are widened rather than reduced in high-risk tumours.

Why is "A benign incidental finding" not the answer?

Tumour around nerves is not benign, and numbness shows nerve involvement.

Why is "A feature seen only in basal cell carcinoma" not the answer?

It occurs in squamous cell carcinoma too, and is not exclusive to basal cell carcinoma.

What concept does this question test?

It tests Skin tumours: perineural invasion in squamous cell carcinoma in Dermatology. Other high-risk features include thickness, poor differentiation, immunosuppression and recurrence. Such tumours often warrant wider excision or Mohs surgery with adjuvant radiotherapy.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Skin tumours: perineural invasion in squamous cell carcinoma?

Learn each condition by its primary lesion, site and signature sign. Then use the flashcards and the other Dermatology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.