Dermal cylindroma
Dermal cylindroma treated with X-rays without recurrence

In dermatologic pathology, a dermal cylindroma, also dermal eccrine cylindroma or cutaneous cylindroma^[1]: 666) and (less specifically) cylindroma, is a benign adnexal tumor^[2] that occurs on the scalp and forehead.

Multiple cylindromas may grow together in a "hat-like" configuration, sometimes referred to as a turban tumor.^[3] Cylindromas are uncommon dysplasias of skin appendages.^[4]

Dermal cylindromas are:

• Dermal lesions consisting of nests of cells that are surrounded by hyaline (i.e., glassy, eosinophilic, acellular) material and have:
  • Hyperchromatic nuclei that may palisade (columnar nuclei arranged around the periphery of the cell nests with their short axis tangential to the nest periphery), and
  • Cells with lighter staining ovoid nuclei at their centre.

They lack of a significant number of lymphocytes; this differentiates them from spiradenomas.

• 
  Micrograph of a dermal cylindroma in H&E stain.
• 
  Micrograph of dermal cylindroma in H&E stain.
• 
  Dermal cylindroma. Puzzle-like distribution of tumour foci.
• 
  Dermal cylindroma. Hyaline droplets visible in lobules.
• 
  Dermal cylindroma, micronodular type.

• Spiradenoma
• Malignant acrospiroma