Benign granular cell tumor of the uterine corpus: A case report

Abstract

Objective: Granular cell tumors (GCTs) are relatively uncommon soft tissue tumors that are usually benign (0.5-2.0% malignant). They have been described in many sites and organs, although cases with genital involvement have rarely been reported. We present the clinicopathological features of a case of a uterine corpus GST. Methods: A 37-year-old woman with secondary infertility was admitted at the University Clinic of Gynecology and Obstetrics for a hysteroscopic examination during which a polypoid isthmico-cervical lesion was detected. Results: The biopsy excision specimen consisted of one smaller fragment of the endometrium and two larger semispherical fragments measuring 0.7x0.5x0.4 and 0.8x0.6x0.4 cm. Upon microscopic examination of the larger fragments under the partly pseudodecidualized endometrial or isthmic type of surface mucosa, a benign mesenchymal neoplasm was found composed of nests of large polygonal cells with an abundant eosinophilic granular cytoplasm and round to oval nuclei lacking conspicuous nucleoli or mitotic figures. In addition to PAS positivity, upon immunohistochemical staining, the large cells also showed vimentin, S-100, neuron-specific enolase, CD56, CD57, calretinin and Wilms tumor 1 positivity. The proliferative index determined by Ki-67 staining was <5%. Based on the pathological and immunohistochemical examinations, the diagnosis of a benign GCT was established. Due to the fact that the neoplasm was incompletely excised a wide local excision was recommended along with a careful follow-up of the patient. The patient refused the excision and is being well and preparing for in vitro fertilization 24 months following biopsy. Conclusion: GCTs of the uterus and especially of the uterine corpus are extremely rare. To the best of our knowledge, this is a second reported case of uterine corpus GCT in the English-language literature. It is important for gynecologists as well as pathologists to be aware of the possibility of uterine corpus GCTs, for which accurate diagnosis, complete resection and long-term follow-up are crucial.