Papillary syringoadenoma: causes, symptoms, diagnosis, treatment

Papillary syringoadenoma (syn.: papillary eccrine adenoma, papillary syringocystadenoma, papillary syringocystadenomatous nevus; papillary tubular adenoma is a rare tumor, localized more often on the skin of the distal parts of the extremities in the form of a clearly defined hemispherical nodule, sometimes with a semi-translucent wall, 0.5-1.5 cm in diameter. Occasionally, erosion occurs in the central part. The age of patients varies widely - from 9 years to 81 years. In most cases, patients are over 40 years old. The ratio of men and women is 1:5.

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Pathomorphology of papillary syringoadenoma

Papillomatosis is expressed in the area of the element, epidermal growths penetrate into the dermis with the formation of cysts. The tumor parenchyma consists of papillary growths (papillomatosis), covered with two- or multi-row glandular epithelium. The cells facing the lumen are tall, prismatic, with oval nuclei and eosinophilic cytoplasm, usually with signs of active holocrine secretion. The cells facing the dermal surface are small, cuboidal with rounded dark nuclei and scanty cytoplasm. The papillae are rich in stroma with lymphohistiocytic infiltration. In addition to papillae and cysts, intertwined tubular structures lined with a two-layer epithelium are often found in the tumor. In the lumens of the tubules, there is abundant granular eosinophilic PAS+ content, resistant to diastase, and necrotic detritus. Some regard it as necrotic epithelium, others as a substance released during secretion. The epidermis above the papillae is often ulcerated, with acanthosis at the edges of the ulceration. The diagnostic feature of papillary syringoadenoma is the presence of a dense plasmacytic infiltrate in the dermis, especially in the papillae of the tumor stroma. Often, undeveloped sebaceous glands and hair structures are found in the tumor.

Histogenesis of papillary syringoadenoma

There is still no complete clarity regarding the histogenesis of papillary syringoadenoma, since not all cases of this tumor have the classic secretory features of apocrine glands. Thus, electron microscopic examination has shown partially ductal, partially eccrine secretory differentiation of tumor elements; in addition, K. Hashimoto et al. (1987) identified EKH5 and EKH6 in the epithelial cells of the tumor - antikeratin antibodies, which, according to the authors, are specific for eccrine differentiation. K. Nizume (1976), on the contrary, revealed differentiation in the direction of the intrafollicular and intradermal sections of the embryonic apocrine glands. Using histochemical methods, M. Landry and R. Winkelmann (1972) identified histoenzymatic criteria for apocrine secretion (pronounced endoxylesterase and acid phosphatase activity), while phosphorylase, an enzyme characteristic of exocrine cells, is not detected in this tumor. Such discrepancies in the assessment of the histogenesis of papillary syringoadenoma allow some authors to assert that this nosological form actually represents a composite group of neoplasms, partly with eccrine and partly with apocrine differentiation.

Malignant analogues of eccrine hidradenomas, according to O.R. Hornstein and F. Weidner (1979), are malignant eccrine poroma (porocarcinoma), malignant clear cell hidradenoma, adenoid cystic or chondroid type of adenocarcinoma, which was included in the WHO classification (1980) under the name "chondroid syringocarcinoma".