Primary Pleomorphic Rhabdomyosarcoma of Thyroid Gland in an Adult Patient: A Case Report

Abstract

Thyroid sarcoma is a very rare entity, accounting for less than 1% of all malignant thyroid tumours. Rhabdomyosarcoma (RMS) is a sarcoma subtype, which is more common in children and adolescents. In this case, a 68-year old man, presented with hoarseness and diagnosed with pleomorphic RMS, was explored. No study of primary thyroid pure RMS has been reported in the literature, with the exception of the case reports of differentiated RMS.

Keywords: Pleomorphic rhabdomyosarcoma; adult; thyroid cancer.

Figure 1. a–c.

Tomography Scanning of the case: Axial contrast enhanced CT images (a, b) at the level of cervical trachea show a heterogeneous hypoattenuating mass in the right posterior thyroid gland. Coronal reformatted contrast enhanced CT image (c) it is demonstrated that mass extends the retrosternal space.

Figure 2. a, b.

Histopathological and immunohistochemical imaging of the case: a) Most of the tumour cells are spindled and arranged in interlacing fascicles. The nuclei are large and pleomorphic, and mitotic figures are easily found (10×). A minor component of the tumour displays “rhabdoid” tumour cells with distinct cytoplasmic borders, voluminous pink to red cytoplasm, eccentric nuclei and prominent nucleoli (100×). b) Immunohistochemical positive staining for desmin.