Cysts:

Hydrocystoma -Eccrine/Apocrine

Hamartomas:

Eccrine/Apocrine naevus

Eccrine Angiomatous Hamartoma

Porokeratotic eccrine ostial naevus

Benign Neoplasms:

Syringocystadenoma Papilliferum

Hidradenoma Papilliferum

Nipple Adenoma

Syringoma

Spiradenoma

Cylindroma

Chondroid Syringoma (benign mixed tumour)

Poroma

Hidradenoma

Apocrine adenoma

Papillary eccrine adenoma

Syringofibroadenoma

Eccrine ductal carcinoma is an exceedingly rare malignant sweat gland neoplasm composed of multiple ductal structures lined by pleomorphic cuboidal cells.  The tumour has an infiltrative pattern. Focal solid and cribriform areas are also present. Mitotic activity is prominent. There is usually no evidence of decapitation secretion.

Images:

Differential diagnosis:  Primary and metastatic ductal carcinoma of breast and salivary gland.

Ductal eccrine carcinoma presenting as a Paget's disease-like lesion of the breast.Breast J. 2001 Sep-Oct;7(5):358-62.

Carcinomas of sweat glands: report of 60 cases.Arch Pathol Lab Med. 2001 Apr;125(4):498-505.

Homologous carcinomas of the breasts, skin, and salivary glands. A histologic and immunohistochemical comparison of ductal mammary carcinoma, ductal sweat gland carcinoma, and salivary duct carcinoma.Am J Clin Pathol. 1998 Jan;109(1):75-84.

Squamoid eccrine ductal carcinoma.Histopathology. 1997 Mar;30(3):288-93.

Histologic spectrum of carcinomas with eccrine ductal differentiation (sweat-gland ductal carcinomas).Am J Dermatopathol. 1993 Oct;15(5):435-40.