Other cutaneous lesions

Question 1

Merkel cell carcinoma is what type of tumor?

Answer 1

Neuroendocrine. It arises from Merkel cells, which are
specialized touch receptors, found in the basal layer of the
epidermis. They are very aggressive. Pathologic nodal
staging (neck dissection) has been associated with better
survival, as 23% of patients with no clinical evidence of
nodal disease were found to have positive nodes on neck
dissection.

Question 2

What is the relationship between Merkel cell
polyoma virus (MCV) and Merkel cell carcinoma
(MCC)?

Answer 2

About 80% of Merkel cell carcinoma tumors have cells that
exhibit MCV infection. MCV infection is widespread among
humans, but it is thought to be an important factor in most
MCCs.

Question 3

What immunohistochemical stains are used for

MCC?

Answer 3

Cytokeratin 20 (CK20), chromogranin, Cam5.2

Question 4

A patient has a rapidly enlarging 6-cm cystic mass
of the scalp. Excisional biopsy shows deep dermal and subcutaneous involvement, which histologically shows evidence of a squamous-lined cyst with extensive trichilemmal keratinization. What is the most likely diagnosis?

Answer 4

Proliferating trichilemmal cyst

Question 5

What is the recurrence rate of microcystic adnexal
tumors treated with wide local excision compared
with those treated with Mohs surgery?

Answer 5

Wide local excision 60%, Mohs surgery 0 to 12%

Question 6

A patient presents with an 8-mm lesion on the
upper lateral eyelid. Biopsy shows neoplastic cells
with sebaceous differentiation and cytoplasmic
vacuolization. What is the preferred treatment?

Answer 6

Sebaceous carcinoma is an aggressive tumor with a proclivity for metastasis. Mohs surgical resection is associated with lower local and distant recurrence rates.

Question 7

What are syringomata?

Answer 7

Syringomata are benign sweat gland tumors that com-
monly occur in multiples. They are more common in
women and occur predominantly on the face at the eyelids, upper cheeks, and neck.

Question 8

What is a pilomatrixoma?

Answer 8

Benign appendageal tumors that commonly affect the head
and neck and contain a differentiation toward hair cells;
rarely associated with carcinoma

Question 9

What is the typical clinical presentation of a pilomatrixoma?

Answer 9

Single, firm, skin-colored or slightly bluish nodule occurring
on the face, neck, and shoulders

Question 10

What are epidermoid cysts?

Answer 10

Benign cutaneous cysts with epithelial lining that produce
keratinized cellular debris. They usually occur after puberty
and may rupture, drain, or become infected.

Question 11

Which defects require immediate management?

Answer 11

● Periocular defects require early treatment to prevent
ocular damage either with reconstruction or temporary
eye closure.
● Perioral defects with oral contamination should be
reconstructed early to minimize oral contamination.
● Alar defects should be reconstructed early to prevent
tissue contraction.