Adnexal tumors

Adnexal Tumors - A Hairy Situation

• Tumors of skin appendages, classified by origin: hair follicle, sebaceous, apocrine, or eccrine glands.

• Cylindroma: "Turban tumor" on head/scalp. Histology shows nests of basaloid cells fitting like a "jigsaw puzzle."
• Syringoma: Benign eccrine duct tumors, often on eyelids. Ducts have a characteristic comma or "tadpole" shape.
• Trichoepithelioma: Benign follicular tumor. Resembles Basal Cell Carcinoma (BCC) but lacks stromal retraction.

⭐ Brooke-Spiegler syndrome is an autosomal dominant condition caused by a germline mutation in the CYLD gene, leading to multiple cylindromas, trichoepitheliomas, and spiradenomas.

Follicular Tumors - Hair Apparent

• Trichoepithelioma
  • Benign, often multiple papules on the face.
  • Histo: Basaloid islands, horn cysts, abortive hair papillae.
  • Associated with Brooke-Spiegler syndrome (CYLD gene).
• Pilomatricoma (Pilomatrixoma)
  • Solitary, firm, deep nodule; common in children/young adults.
  • Histo: Basaloid cells, eosinophilic "ghost cells", and calcification.
• Trichilemmoma
  • Smooth papule, often on the face.
  • Histo: Lobules of clear cells (glycogen-rich), peripheral palisading.
  • Marker for Cowden syndrome (PTEN mutation).

⭐ Pilomatricoma's key feature is "ghost cells" (anucleated shadow cells) on histology. It's often linked to activating mutations in the β-catenin gene (CTNNB1).

Sebaceous Tumors - Oily Origins

• Sebaceous Adenoma:

  • Benign, slow-growing yellow papule; typically on the head/neck of older adults.
  • Histology: Lobules of mature sebocytes with bubbly, vacuolated cytoplasm mixed with basaloid cells.

• Sebaceous Carcinoma:

  • Malignant, aggressive tumor, often on the eyelid (Meibomian glands).
  • May mimic chalazion or blepharitis, leading to delayed diagnosis.
  • Histology: Infiltrative growth, cellular atypia, necrosis, and pagetoid spread.

⭐ Muir-Torre Syndrome: The presence of any sebaceous neoplasm (especially adenoma) should raise suspicion for this autosomal dominant syndrome, a variant of HNPCC/Lynch syndrome, associated with visceral malignancies (most commonly colorectal cancer).

Sweat Gland Tumors - Hot & Bothered

• Syringoma: Benign adenomas of intraepidermal eccrine ducts. Presents as multiple, small, skin-colored papules, typically around the eyes (periorbital). More common in women.
  • Histo: Tadpole-like ducts.
• Eccrine Poroma: Benign tumor, often a solitary, pink/red papule or nodule on palms or soles of older adults.
• Cylindroma: Benign, slow-growing tumor. Can present as a solitary lesion or multiple nodules on the scalp ("turban tumor"). Associated with Brooke-Spiegler syndrome (AD, CYLD gene mutation).

⭐ On histology, cylindromas are classic for islands of basaloid cells that fit together tightly, resembling a "jigsaw puzzle."

High‑Yield Points - ⚡ Biggest Takeaways

• Cylindromas show a "jigsaw puzzle" pattern and are linked to Brooke-Spiegler syndrome, often presenting as a "turban tumor".
• Syringomas are benign sweat duct tumors, commonly appearing as small papules around the lower eyelids.
• Pilomatricomas are firm nodules with characteristic "ghost cells" on histology and are associated with myotonic dystrophy.
• Sebaceous carcinoma, an aggressive malignancy of the eyelid, is strongly associated with Muir-Torre syndrome.
• Trichoepitheliomas are benign follicular tumors; multiple lesions also suggest Brooke-Spiegler syndrome.