Case report: elevated serum beta human chorionic gonadotropin in a woman with osteosarcoma

Abstract

Human chorionic gonadotropin is a glycoprotein hormone normally synthesized by placental syncytiotrophoblast cells. It also is secreted by gestational trophoblastic tumors, gonadal tumors, and even various nongonadal tumors, including bone and soft tissue sarcomas, as a paraneoplastic syndrome. The literature contains one case report of beta human chorionic gonadotropin production from a primary bone sarcoma occurring in a male patient. We report a woman of childbearing age who presented with a distal femur lytic lesion, clinical symptoms suggestive of pregnancy, and elevated serum beta human chorionic gonadotropin. Although the clinical diagnosis of a sarcoma was never in doubt, we present this case to emphasize a need to exclude pregnancy in women of childbearing age to avoid delay in biopsy and subsequent management. Positive immunohistochemical staining of the biopsy specimen established the tumor cells as the source of beta human chorionic gonadotropin.

Fig. 1A–B

(A) Anteroposterior and (B) lateral radiographs of the initial tumor show a large radiolucent lesion in the distal femoral metaphysis with permeative borders and areas of sclerosis.

Fig. 2

An axial T1-weighted MR image through the distal femur shows a large soft tissue mass affecting all compartments of the thigh. The neurovascular structures cannot be identified because of the massive tumor.

Fig. 3

A photomicrograph of the biopsy specimen shows spindle-shaped tumor cells and a dense, pink osteoid matrix (Stain, hematoxylin and eosin; original magnification, ×100).

Fig. 4

A photomicrograph shows the biopsy specimen with immunohistochemical staining for βhCG (Stain, anti-βhCG, PAP method; original magnification, ×100). Brown pigmentation in the cytoplasm confirms the expression of βhCG by the tumor cells.