Eccrine spiradenoma

Eccrine spiradenoma, also spiradenoma, is (usually) a benign, painful skin thingy. There is case series of malignant ones.

Eccrine spiradenoma
Diagnosis in short
Eccrine spiradenoma. H&E stain.
Synonyms	spiradenoma
LM	dense nests of cells in the dermis ("dermal blue balls"), mixed cell population (epithelial, myoepithelial, +/-lymphocytes)
LM DDx	dermal cylindroma, trichoepithelioma
IHC	S100 +ve, CK7 +ve, CK18 +ve
Site	skin
Symptoms	pain - see painful skin lesions
Prevalence	uncommon
Prognosis	benign
Other	may be related to dermal cylindroma
Clin. DDx	painful skin lesions, others
Treatment	excision

General

• One of the ANGEL tumours:
  • A painful skin lesion.
  • Many of these tumours have a prominent vascular component (think of blood vessels throbbing).
• Benign.
• Usually solitary, circumscribed and dermal.
• Most common on the head.
• Multiple lesions, early in life suggest a genetic syndrome.
  • Brooke-Spiegler syndrome - spiradenomas, cylindromas and trichoepitheliomas
• Generally considered to be an 'eccrine' tumor but some hypothesize a pilar origin

Microscopic

Features:

• Dense nests of cells in the dermis; "dermal blue balls".
• Biphasic cell population:
  • outer dark cells with small hyperchromatic nuclei and minimal cytoplasm.
  • inner larger cells with vesicular nuclei and more cytoplasm.
  • In some areas the two cell types mix together with dispersed hyaline droplets.
• Ductal differentiation.
• These cells form lobules that are surrounded by a hyaline or reticulin sheath.
• +/-Lymphocytes.
• Vascular component - large and small blood vessels.

DDx:

• Dermal cylindroma.
  • These two tumors are very closely related and overlap.
  • Many tumors have areas of both spiradenoma and cylindroma.
  • The lobules of cylindroma are small
    • more consistently discrete,
    • show more a more consistent arrangement of the light and dark cells and are
    • often surrounded by prominent hyaline material.
  • Individual lobules of cylindroma fit together like pieces of a puzzle.
  • Lobules of spiradenoma are larger
    • may run together and fuse,
    • may not have a prominent hyaline surround and
    • may show more disorganization and mixing of the two cell types
• Trichoepithelioma.
  • Trichoepithelioma will show
    • attempts at hair bulbs,
    • areas with more eosinophilic cytoplasm and
    • characteristic peritumoral stroma
• Glomus tumour, hemangioma or hemangiopericytoma (vascular spiradenomas).
  • The location often speaks against glomus tumour.
• Basal cell carcinoma
  • Spiradenoma is deeper, without connection to the epidermis
  • Spiradenoma lacks clefting artefact.
  • Spiradenoma lacks mitoses and prominent apoptosis.
  • BCC lacks ducts
  • BCC lobules lack a prominent surrounding hyaline membrane
• Lymphoid aggregate (spiradenoma will be cytokeratin positive)

Images

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  Eccrine spiradenoma - very low mag. (WC)

• 

  Eccrine spiradenoma - low mag. (WC)

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  Eccrine spiradenoma - intermed. mag. (WC)

• 

  Eccrine spiradenoma - high mag. (WC)

• 

  Eccrine spiradenoma - very high mag. (WC)

• 

  Low power shot of a vascular spiradenoma (SKB)

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  Spiradenoma - vascular channels within a basaloid tumor. (SKB)

• 

  Thrombosed blood vessel within a spiradenoma. (SKB)

• 

  Spiradenoma - dispersed hyaline pattern. (SKB)

www:

• Eccrine spiradenoma (dermimages.med.jhmi.edu).

IHC

Features:

• S100 +ve.
• Keratins 7, 8, and 18 +ve.
• Ductules are EMA and CEA positive.

Notes:

• IHC profile essentially identical to dermal cylindroma.

See also

• Dermatopathology.
• Non-malignant skin disease.
• Painful skin lesions.
• Eccrine carcinoma.