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eccrine spiradenoma

Monday 30 May 2016

PO

Definition: Spiradenoma forms a firm nodule on the face or upper trunk, and can be painful. The lesion is benign. Histologically it shows nests with two types of cells: small hyperchromatic cells at the periphery and larger and paler cells centrally. There is compact PAS+ eosinophilic basement membrane material and infiltrating lymphocytes.

Images

- eccrine spiradenoma

- cystic eccrine spiradenoma

- eccrine spiradenoma nodule in the subcutis

Synopsis

- blue nodula formation with biphasic population : peripheral small basaloid cells and larger paler cells centrally
- lobulated tumor islands separated by thin fibrous tissue containing blood vessels
- benign biphasic basophilic dermal adnexal tumor

  • biphasic appearance : light cells and dark cells / basophilic cells

- circumscribed nodule (s) with hyaline globules
- sharply circumscribed dermal nodule : " blue ball " appearance in dermis
- lobular architecture
- very cellular / high cellularity
- scant cytoplasm
- hyaline globules / eosinophilic hyaline droplets
- presence of ducts / intratumoral ducts

- high vascularity
- variable lymphocytic infiltrate within lesion / interstitial lymphocytes

- Can occur both separately and in combination with cylindromas

Variants

- malignant eccrine spiradenoma

IHC

- CK7+ epithelial and p63+ myoepithelial cells

Differential diagnosis

- cutaneous lymphadenoma
- cutaneous basaloid cell tumors

- cutaneous metastatic carcinoma
- cutaneous synovial sarcoma
- cutaneous thymoma

See also

- cutaneous tumors