Chondroid syringoma with hyaline cell change

Abstract

Four cases of chondroid syringoma containing large numbers of hyaline or plasmacytoid cells are described. Three cases occurred in the hand and one in the foot. Hyaline cells are commonly seen in mixed tumours and myoepitheliomas of salivary glands and rarely in chondroid syringomas. The hyaline-cell change in three of the cases initially caused diagnostic difficulties and the possibility of sarcoma was raised in two cases. In addition to the characteristic hyaline cells, the presence of tubulo-glandulo-ductal structures, benign squamous epithelium and myxochondroid stroma aided diagnosis. Immunohistochemically, the hyaline cells exhibited positivity for vimentin, cytokeratin, S-100 protein, carcino-embryonic antigen, focal glial fibrillary acidic protein (3 cases), neuron-specific enolase (3 cases) and focal alpha-smooth muscle actin (2 cases). Occasional cells were Ber EP4 positive (2 cases). In some cells, a striking peripheral ring-like positivity for cytokeratin and S-100 protein was noted. Ultrastructurally, desmosomes, varying numbers of tonofibrils and non-bundling intermediate filaments were seen. Scanty fine filaments with vague focal densities were detected in some cells. Our studies suggest that the hyaline cells represent modified epithelial as well as myoepithelial cells. One of our cases also exhibited collagenous spherulosis.

Cutaneous myoepithelioma: a clinicopathologic and immunohistochemical study of 14 cases

“…Mixed tumors of the skin show variably prominent myxoid stroma, chondroid metaplasia, and (similar to their salivary gland counterparts) solid foci of spindled or plasmacytoid myoepithelial cells, which occasionally predominate. 7,9,16 In salivary glands, the uncommon diagnosis of myoepithelioma initially was reserved for those tumors composed of solid sheets of spindled or plasmacytoid cells; 18,19 however, it is now recognized that myoepitheliomas can display the same broad morphological range as the myoepithelial component of mixed tumors ("pleomorphic adenomas"), [12][13][14]20 including …”

“…Occasionally, cutaneous mixed tumors demonstrate more nodular solid proliferations of spindled, plasmacytoid (hyaline), or epithelioid cells in myxoid stroma, believed to represent areas of myoepithelial differentiation. [7][8][9] Whereas cutaneous mixed tumors are well described, tumors that exhibit purely myoepithelial differentiation (ie, myoepitheliomas) were only recently recognized to occur primarily in the dermis. 10,11 Because fewer than 10 cutaneous myoepitheliomas have been reported to date, their description has been limited.…”

Myoepitheliomas of the skin and soft tissues

“…Antibody to type III collagen stains peripheral parts of the collagenous crystalloids, but they usually lack immunohistochemical staining with antibody to laminin and type IV collagen [32]. They occur in 5% of the myoepitheliomas and mixed tumours of the salivary glands [3,32], but have rarely been described in mixed tumours of the skin [1,2]. These crystalloids are not specific for myoepithelioma and mixed tumours of the skin, having also been described in basal cell carcinomas of the skin [33,37].…”

Apocrine mixed tumor of the skin (“mixed tumor of the folliculosebaceous-apocrine complex”)

“…Collagenous spherules have also been identified in salivary gland tumors where they occur in 5% of pleomorphic adenomas and myoepitheliomas, but similar features have also been recognized in kidney, endometrium, and even in nonepithelial tumors, including schwannoma. [71][72][73][74][75][76] In cutaneous adnexal tumors, aside from their occurrence in a few cases of AMT, 46,77,78 they have rarely been identified in apocrine hidradenoma, 48 myoepithelioma, 79 and basal cell carcinoma. 80 Immunohistochemically, the collagenous spherules display strong and homogeneous staining for type I collagen; type III collagen occurs peripherally in the collagenous crystalloids, while laminin and collagen IV are never found.…”