Neuroendocrine carcinomas associated with squamous cell carcinomas of the uterine cervix: Light and electron microscopic observations in two cases

Abstract

Small cell carcinomas are rare in cervical cancers and appear to be a heterogeneous group of tumors. Neuroendocrine carcinoma of the cervix, one subtype of small cell carcinomas of the cervix, can be identified by characteristic light and electron microscopic criteria. Two cases of neuroendocrine carcinomas associated with squamous cell carcinomas of the uterine cervix are reported in which electron microscopic studies were performed. The presence of small dense-core membrane-bound granules (120 to 160 nm) in cytoplasmic process under electron microscopic observation confirmed the diagnosis of neuroendocrine carcinoma of the cervix. The coexistence of electron dense-core membrane-bound granules, abundant tonofibrils, and desmosomes within the cancer cells, suggests that these tumors may have derived from the multipotential precursor cells with neuroendocrine and squamous differentiation. Because neuroendocrine carcinomas appear to have the highest incidence of recurrence and the poorest prognosis, it is necessary to distinguish these neoplasms from squamous cell carcinomas of the cervix. Literature about neuroendocrine carcinomas of the cervix is also reviewed.