Adnexal Neoplasms

Question 1

Answer 1

Syringoma

• Multiple small felsh-colored papules on woman’s face
• Bland ductal structures with cords and tadpoles in fibrotic stroma
• DDX: desmoplastic trichoepithelioma (follicular diff’n and calcs)

Question 2

Answer 2

Chondroid syringoma

(mixed tumor of the skin)

dermal epithelial islands and branching strands containing ducts surrounded by abundant myxoid to chondroid stroma

Question 3

Sites

Describe histology

DDX

Answer 3

Poroma

“eccrine poroma”

Often acral sites

Anastomosing strands of bland adnexal keratinocytes

Originates from epidermis and extends into dermis

Focal duct formation

(related to hidradenoma - mainly in dermis- and dermal duct tumor)

Question 4

Answer 4

Spiradenoma

• “eccrine spiradenoma”
• lobules and nest of adnexal cells with central luminae
• contains 2 epithelial cell layers (smaller outer and larger inner)
• Eosinophilic hyaline droplets
• Cystic spaces
• prominent vessels with hemorrhage (not as common in cylindroma)
• Painful

Question 5

Answer 5

Cylindroma

• jigsaw puzzle
• nests separated by thick basement membrane (also within nests)
• occasional ducts (less than in spiradenoma)
• hyaline droplets
• Brooke Spiegler

Question 6

Answer 6

Dermal duct tumor

Question 7

Answer 7

Hidradenoma (aka acrospiroma)

• Nodular, solid (first picture), and clear cell (second picture) types
• Variable ductal differentiation
• Basically the same as dermal poroma, dermal duct tumor

Question 8

Answer 8

Hidradenoma papilliferum

• Perineal region of women
• dermal-based nodule of tubular and cystic structures with apocrine differentiation

Question 9

Describe histology

Location

DDX

Immunos

Answer 9

Microcystic adnexal carcinoma

• Depressed plaque on face, esp upper lip of adults
• Superficial bland follicular crusts overlying deeply infiltrative epithelial strands with follicular and sweat duct formation, often perineural invasion

DDX:

• Sclerosing BCC - lacks superficial follicular cysts and ductal differentiation
• Desmoplastic trichoepithelioma - lacks deep invasion or perinerual invasion, has calcs, follicular but no ductal differentiation

Immunoperoxidase - CK7 and EMA Positive (negative in BCC and TE) and low ki-67 and p53 (high in BCC)

Question 10

Histology

Location

Immunos

Answer 10

Extramammary paget’s disease

• Eroded plaque often genital or perineal (also axillae and eyelid)
  Pagetoid intraepidermoid spread of large atypical cells with occasional signet ring cells or gland formation
• Mucin
• PASD+
• Immunoperoxidase:
  
  • GCDFP+
  • CEA+
  • CAM5.2+
  • EMA+
  • CK7+
  • CK20-
  • S100-

Question 11

Answer 11

Sebaceous adenoma

• May indicate Muir Torre syndrome (HNPCC associated with MLH1, MSH2, MSH6)
• Circumscribed
• > 50% well-differentiated sebocytes

Question 12

Answer 12

Sebaceoma

Clinical: a/w Muir Torre syndrome

Histo:

1. circumscribed growth
2. < 50% well-differentiated sebocytes
3. > 50% bland basaloid cells

Question 13

Answer 13

Sebaceous carcinoma

Clinical: eyelid and extraocular; aggressive tumor with frequent mets

Histology:

1. infiltrative
2. pagetoid spread
3. atypia
4. squamous or basaloid differentiation, but should find vacuolated cells

Immunoperoxidase:

1. CAM5.2 +
2. androgen +
3. EMA +/- (lost in poorly differentiated)
4. CK7 +/-
5. GCDFP-
6. CEA-

Question 14

Answer 14

Trichoepithelioma

Basaloid, cribriform nodules with finger-like projections

Type of trichoblastoma

Seen in Brooke-Spiegler and Rombo syndromes

Mucin may be present in nests, but not in stroma

Multiple small papules in the nasolabial folds

Resemble BCC, but unlike BCC it has:

1. concentric fibroblast-rich stroma instead of myxoid stroma
2. papillary mesenchymal bodies
3. horn cysts
4. calcification
5. clefts between collagen fibers within stroma not between nodules and stroma
6. CD34+ stroma
7. Peripheral positivity for BCL2 whereas BCC has strong, diffuse staining
8. Ber-EP4 +/- (BCC strong positive)

Question 15

Answer 15

Trichoblastoma

Large, deep nodular proliferation

Question 16

Answer 16

Desmoplastic trichepithelioma

Infiltrating epithelial structures with cords and tadpole shapes in a fibrotic stroma

follicular differentiation and calcs are frequent (unlike infiltrating/sclerosing BCC)

DDX:

MAC

Morpheaform BCC

Immunoperoxidase: p53, Ki-67 negative (+ in BCC) and CK7 - (positive in MAC)

Question 17

Answer 17

Pilomatricoma

Calcifying epithelioma of Malherbe

Clinical: head and neck nodule in kids or young adults

Nodular or cystic proliferation of hyperchromatic basaloid cells merging with central shadow cells; calcs and ossification