Pathology of Syringocystadenoma Papilliferum

Syringocystadenoma papilliferum is an adnexal tumour which commonly occurs on the scalp, forehead or face.

Rarely these tumours are found on the trunk, the lower extremities, ear canal and eyelid.

It was first described as "nevus syringadenomatosus papilliferus" by Stokes in 1917.

The origin of this tumour is still being debated.

The results of light, electron microscopic, immunohistochemical and anatomic studies are conflicting.

Many authors believe that syringocystadenoma papilliferum is mainly apocrine derived tumour because of the occasional presence of decapitation secretion in some of the luminal cells of the tumour and the frequent presence of tubular glands with large lumina and decapitation secretion beneath the tumour.

In some lesions, where there are no apocrine glands in the dermis, the papilliferous structures represent eccrine proliferation.

Most authors agree that this hamartoma develops from undifferentiated pluripotential appendageal cells.

Clinical presentation:

Clinically, most of the cases are first noted at birth.

Other cases develop in infancy, childhood and adolescence.

The tumour presents either as one papule or several papules in a linear arrangement, or as a solitary plaque.

Some papular lesion may be umbilicated and resemble molluscum contagiosum.

During evolution of lesion verrucous changes can develop at puberty.

The plaque type lesion is similar to nevus sebaceous.

Microscopic features:

Epidermis is acanthotic and shows papillomatosis.

A cystic invagination extends downward from the epidermis.

Numerous villous projections are seen within these invaginations.

These papillary projection are lined by two layers of epithelial cells, a columnar luminal cell layer and an outer layer of small cuboidal cells.

Occasionally, the luminal row of cells show decapitation secretion.

In the deep dermis, groups of apocrine glands may be present. Close step sections should be carried out, to demonstrate connection of the apocrine glands with cystic invagination in the upper dermis.

The stroma is usually infiltrated by a dense mononuclear infiltrate composed entirely of plasma cells.

Malformed sebaceous glands and hair structures may be present.

Syringocystadenoma papilliferum may be associated with nevus sebaceous and basal cell carcinoma and rarely with sebaceous epithelioma, trichoepithelioma, eccrine spiradenoma and apocrine hydrocystoma.

Syringocystadenocarcinoma Papilliferum:

Syringocystadenocarcinoma papilliferum is a distinct dermatologic entity.

This exceedingly rare neoplasm, most examples of which seem to have arisen in its benign counterpart, syringocystadenoma papilliferum.

Histologically, this malignant tumour shows in-situ adenocarcinoma with cytological atypia and pagetoid spread into surrounding epithelia.

The tumour lacks typical double layered pattern.

Decapitation secretion is present.

Immunohistochemistry shows immunoreactivity to EMA and human milk fat globules.

-Syringocystadenocarcinoma papilliferum: case report and immunohistochemical comparison with its benign counterpart.

-Syringocystadenocarcinoma papilliferum with squamous cell carcinoma differentiation and with locoregional metastasis.

-A case of syringocystadenocarcinoma papilliferum in situ occurring partially in syringocystadenoma papilliferum.

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