Massive osteolysis in a girl with agenesis of thyroid C cells

A rare case of massive osteolysis affecting the pelvis of a young girl is presented. The clinical, radiographic, and histopathological features are described in detail. Septicemia complicated the clinical course and the patient eventually died. Histopathological examination of the pelvic lesion revealed massive osteolysis characterized by prominent osteoclastic activity with extensive bone resorption. A thorough post-mortem histological examination of the thyroid gland showed no C cells. This is an interesting observation, since it is known that thyroid C cells are the primary source of calcitonin. Since the main biological effect of calcitonin is to inhibit osteoclastic bone resorption, there is a possibility that massive osteolysis in our case could have been related to the lack of this hormone. There is a clear need for further investigation regarding the role of thyroid C cells and calcitonin in this puzzling disease.