CASE REPORT   

Il Giornale Italiano di Radiologia Medica 2019 Novembre-Dicembre;6(6):586-93

DOI: 10.23736/S2283-8376.19.00237-7

Copyright © 2019 EDIZIONI MINERVA MEDICA

language: English, Italian

A rare case of granular cell tumor

Alberto PACIELLI ¹ ✉, Fatemeh DARVIZEH ¹, Annalisa OPPEZZO ², Alekos BOMPOTSIARIS ², Emanuela BALMA ¹, Paolo FONIO ¹

¹ Institute of Radiology, San Giovanni Battista University Hospital, University of Turin, Turin, Italy; ² Division of Diagnostic Radiology, Sant’Andrea Hospital, Vercelli, Italy

Granular cell tumor (GCT) is a rare mesenchymal neoplasm of neurogenic origin, with numerous localization sites reported in the literature. Almost all GCT cases exhibit benign behavior, with less than 2% incidence of malignancy. GCTs affect female more often with age range between 20 and 40 years old. In this case report we evaluated a 63-year-old female patient with malignant granular cell tumor of knee. Magnetic resonance imaging (MRI) showed a mass with an isointense signal respect to the normal muscular tissue in T1 sequence, a hyperintense on T1 fat-sat and T2 fat-sat with hypointense septae. Moreover, GRE T2* sequence demonstrated a hypointense area in lower part of the mass and inhomogeneous contrast enhancement after administration of contrast agent. After non-specific findings on MRI, surgical excision with subsequent histological analysis was performed to make a definite diagnosis. The microscopic examination illustrated multiple intersected bundles of spindle-shaped cells and, to a lesser extent, polygonal cells with nuclear atypia and granulated eosinophilic cytoplasm, PAS+. Additionally, the presence of a rich vascularization and invasive behavior into adjacent adipose tissue highlighted the malignant nature of the tumor, with definitive diagnosis of malignant granular cell tumor. Combined modality treatment with radiotherapy and chemotherapy was used with subsequent MRI follow-up for the primary lesion and eventually chest X-ray/CT was utilized to rule out any lung metastasis.

KEY WORDS: Granular cell tumor; Magnetic resonance imaging; Knee joint