Chondroid syringoma: causes, symptoms, diagnosis, treatment

Chondroid syringoma (syn.: mucinous hidradenoma, the so-called mixed skin tumor) occurs predominantly in men, can be observed on various parts of the body, but most often on the scalp, face and neck. The tumor in the form of a small nodule is located either in the dermis or protrudes slightly above the surface of the skin, its surface is smooth, sometimes with a translucent wall, occasionally ulcerated. On palpation, the tumor is of a dense elastic consistency. Growth is slow, can exist for years. Clinically, it resembles cystic basalioma.

[ 1 ], [ 2 ], [ 3 ], [ 4 ]

Pathomorphology of chondroid syringoma

The histological structure of the tumor is quite diverse, but in all cases there is an epithelial component and proliferation of connective tissue with signs of myxomatosis, often with the formation of chondroid areas. The ratio of the epithelial and connective tissue components varies widely. WF Lever and G. Schaumburg-Lever (1983) distinguish two histological types of the epithelial component: tubular and cystic. A tubular-type tumor consists of numerous narrow strands with branches lying in a hyaline-mucinous stroma. The lumens of the tubular structures are lined with two layers of epithelial cells: some of them face the lumen and have a prismatic shape, while others (on the periphery) are flat. In addition, the mucoid stroma contains single or conglomerate proliferating flat cells. In most cases, the lumens of tubular structures contain amorphous eosinophilic PAS-positive diastase-resistant substance.

The cystic type of tumor consists mostly of small cystic cavities, as well as small groups and strands of epithelial cells. Their lumen is covered with only one layer of flat epithelial cells, from which proliferates extend into the stroma in the form of "tails". The tumor stroma is basophilic and contains mucoid substances. Fibroblasts and individual epithelial cells located in it have a light halo, which resembles cartilage cells. When stained with toluidine blue, metachromasia resistant to hyaluronidase is detected, which indicates the presence of chondroitin sulfates in the tumor.

Histogenesis of chondroid syringoma

Electron microscopy has demonstrated the eccrine differentiation of this tumor. The internal cells of the tubular structures resemble the dark and light cells of the terminal sections of the eccrine glands, and the external flat cells resemble myoepithelial cells, since they contain a large number of filaments and are distributed within the chondroid matrix they produce.

Differential diagnosis is based on the presence of adenoid and epithelial cords in this tumor, as well as chondroid cells in the mucinous stroma. Mixed tumor of the salivary glands has only morphological similarity with chondroid syringoma, but their histogenesis is different.