Small Cell Undifferentiated Carcinoma of the Uterine Cervix: Histology, Ultrastructure, and Immunohistochemistry of Two Cases

Abstract

Two clinical stage IB small cell undifferentiated carcinomas (SCUC) of the cervix were studied by light and electron microscopy and immunohistochemistry. Both cases occurred in women aged less than 31 years. Despite radical hysterectomy and external pelvic radiotherapy, both patients died of recurrent disease within 14 months after initial therapy. The tumors consisted of sheets of closely packed, uniform small, round to oval cells with hyperchromatic nuclei and scant indistinct cytoplasm. One case was associated with cervical squamous cell carcinoma. The neoplastic cells had few organelles and desmosome-like junctions and lacked mucinous or neurosecretory granules or tonofilaments. Immunohistochemistry failed to reveal S-100, CEA, neuropeptides or neuron-specific enolase. SCUC probably arises either from basal cells of the cervical squamous epithelium, or gland cells of the endocervical epithelium, or still from subcolumnar endocervical reserve cells. Based on ultrastructure and immunohistochemistry, SCUC seems to represent the undifferentiated variant of small cell neuroendocrine tumors of the cervix.