Case 1: These tumors form multiple basophilic nodules in the dermis. The tumor nodules are sharply circumscribed and may demonstrate retraction artifact - which may cause confusion with basal cell carcinoma. Amongst the tumor cells are lymphocytes, basement membrane material and dilated vascular spaces.
At higher power, one can see the influx of intratumoral lymphocytes and the dilated vascular channels. Mitotic activity is low.
The basaloid cells tend to form rosettes. Notice the cells are very bland without mitoses or significant atypia.
Eccrine spiradenomas are tumors of the eccrine sweat glands, a dermal appendage normally located alongside hair follicles in hair-bearing skin. They are generally sporadic, but the familial form is inherited in an autosomal dominant fashion, and the responsible gene, CYLD.
Histologically, nodules "blue balls" of basaloid cells are seen in the dermis or subcutis. The tumor cells themselves come in two types: small dark basaloid cells and larger cells with a pale nucleus, found at the periphery of the tumor. There is usually no connection to the overlying epidermis (unlike poromas and a subset of hidradenomas). The basaloid cells tend to arrange themselves in rosettes, and there may be a sparse scattering of sweat duct lumina. Lymphocytes are present in the stroma as well as within the neoplastic cells (Rapini). Unlike cylindromas, the tumor nodules do not fit together like a jigsaw puzzle.
Immunohistochemical staining is usually not necessary but the tumor cells stain positively for IKH-4 (a marker of eccrine differentiation), CK7, CK18, EMA and CEA.
Spiradenomas usually occur singly as a small (<1cm), painful, pink/gray papule on the head and neck of adults in their 2nd to 4th decade. There is a predilection for females. Multiple eccrine spiradenomas along with cylindromas and trichoepitheliomas on the head and neck can be associated with Brooke-Spiegler syndrome - often referred to as 'turban tumors' (Patterson).
Treatment is primarily excision for either cosmetic purposes or to rule out a more aggressive lesion. However, in cases of spiradenomatosis or large, vascular lesions - the treatment may be focused on intratumoral chemotherapy, with resection being reserved to lesions suspicious for eccrine spiradenocarcinoma.
Eccrine spiradenomas are benign and do not metastasize. However, they can transform into eccrine spiradenocarcinoma, which occurs in older individuals and may not necessarily occur on the head and neck - in fact, this site is less common than other sites such as the extremities (McKee). The treatment for eccrine spiradenocarcinoma is wide excision.
McKee PH, Calonje E, Granter S. Pathology of the Skin with Clinical Correlations. 3rd Ed. Philadelphia, PA: Elsevier; 2005: Page.
Patterson JW, Wick MR. Nonmelanocytic Tumors of the Skin.4th Series. Washington, DC: American Registry of Pathology; 2006: Page.
Rapini RP. Practical Dermatopathology. Philadelphia, PA: Elsevier; 2005: 301.