A compound follicular-parafollicular cell carcinoma of the thyroid: A new tumor entity?

Abstract

An unusual thyroid carcinoma is described, showing structural, histochemical and radioimmunologic features of both a follicular and a parafollicular cell carcinoma. Radioimmunoassay revealed high levels of thyroglobulin in the patient's serum and in extracts from metastatic tumor tissue. Immunoreactive thyroglobulin was demonstrated histochemically in tumor cells. On scanning, pulmonary metastases showed uptake of 131I. Somatostatin and neurotensin immunoreactivity was also revealed histochemically in the tumor and a large proportion of the neoplastic cells were argyrophil. Serum calcitonin level was normal and no immunoreactive calcitonin was found in tumor tissue by radioimmunoassay or histochemically. Light microscopy showed cribriform patterns suggestive of follicular carcinoma as well as solid areas reminiscent of medullary carcinoma. Electron microscopy revealed two types of tumor cells. One type had electron dense granules resembling secretory granules characteristic of polypeptide hormone and/or monoamine producing endocrine cells. The other type had no such granules but showed a prominent vesicular rough endoplasmic reticulum similar to that seen in neoplastic follicular cells. The results suggest two alternative possibilities regarding the histogenesis of the tumor. One would be a mixed neoplasm, resulting from a coincidental malignant change in both follicular and parafollicular thyroid cells. The other, more likely alternative would be that the tumor cells are derived from a common stem cell with the potentiality of differentiating into both follicular and parafollicular adult cells. The finding that both thyroglobulin and somatostatin or neurotensin immunoreactivity occurred together in some tumor cells supports the latter possibility and suggests that at least some follicular and parafollicular cells may have a common precursor origin.

Expression of v-Ha-ras driven by the calcitonin/calcitonin gene-related peptide promoter: a novel transgenic murine model for medullary thyroid carcinoma

“…However, human MTCs have been described in which ultrastructural and histochemical features of both parafollicular and follicular epithelial cells are expressed within the same cell (Holm et al, 1987;Kovacs et al, 1994). The existence of these tumors, termed mixed medullary and follicular carcinomas, forms the basis for the proposition that C-cells and follicular cells might share a common embryological origin (Ljungberg et al, 1983;SobrinhoSimoes et al, 1985).…”

Cohexisting Medullary and Papillary Thyroid Cancer

“…Apel et al (6) first proposed the term of "composite thyroid carcinoma." This can be explained if we consider the theory of a common stem cell, proposed by Ljungberg et al (7). According to this theory, the ultimobranchial body is the most likely source of this putative common stem cell because the nests of these cells in the thyroid gland show immunoreactivity for both thyroglobulin and calcitonin, suggesting that the ultimobranchial body may contribute to both parafollicular and follicular cells (6,7).…”

Carcinoma medular da tireóide

“…Além da ausên-cia de amilóide, o diagnóstico pode ser dificultado pela presença de padrões de crescimento atípicos, como papilar (29), folicular (30), tubular (31) e outros (32). Além disso, foram relatados vários casos de tumores exibindo tanto características medulares como foliculares (33,34,35), assim como uma variante anaplásica do CMT (36,37). Há descrição de casos de CMT com imunorreatividade à CT e à tireoglobulina nas mesmas células neoplásicas (38).…”