Malignant granular cell tumor of the breast: case report and literature review

Abstract

Granular cell tumors (GCTs) are uncommon soft tissue tumors that mostly occur in patients between 40 and 60 years of age and can occur at various body sites. Malignant granular cell tumors (MGCTs) comprise less than 2 % of GCTs and are mostly found on the lower extremities, especially the thighs. These tumors grow more rapidly than benign GCTs, and most importantly, they can metastasize. We describe an MGCT that presented as a right breast mass in a 79-year-old Japanese woman. Local excision was performed for the primary tumor, which was diagnosed as an atypical GCT, but 15 months later, the tumor recurred at the same site. Thereafter, right mastectomy with axillary lymph node dissection was performed. Metastatic disease was identified in 2 of 12 lymph nodes. The pathological examination revealed that the tumor had progressed to an MGCT after recurrence. Multiple liver, lung and bone metastases were revealed 4 months after the second surgery, and the patient died 34 months after the primary surgery. Our findings highlighted the difficulty in diagnosing MGCTs using histological features alone and suggested the usefulness of Ki67 values. A tumor with a high level of Ki67 should be treated as malignant, even if the tumor has few pathological features of malignancy.

Granular cell tumor in axillary region: A rare entity

“…In contrast to clinical findings, mammography, ultrasonography and MRI positron emission tomography (PET) with 2-[fluorine-18] fluoro-2-deoxy-d-glucose (FDG) can correctly differentiate GCT from a malignant tumor (11). Fine-needle aspiration cytology and frozen section methods are inadequate for definitive diagnosis of GCT (12). The large core-needle biopsy did accurately predict a GCT in our patient.…”

“…Malignant forms of GCTs are very rare (1-3% of all GCT cases). Chen et al (6) and Akahane et al (12) described malignant GCTs in breast. Criteria for malignancy are not consistent; adjacent tissue and/or vascular invasion, high mitotic activity, and size >4-5 cm were discussed, but only the presence of metastases was accepted as explicit criterion (6,7).…”

Multi‐focal, multi‐centric granular cell tumours: a management dilemma

“…In our case it was difficult to definitively distinguish metastatic tumours from multi‐centric/synchronous “benign” tumours. Both tumours had low FDG uptake on PET scan where some studies have shown that malignant GCTs are usually intensely FDG avid . On imaging, the caecal lesion was larger than the pulmonary lesions and was calcified, the latter often a sign of chronicity.…”

Recurrent Benign Granular Cell Tumor of Breast with Malignancy – Does it Exist?

“…Jardines L, et al [7] reported soft tissue GCT with uncertain malignant potential histologically but had regional nodal metastasis radiologically. Akahane K, et al [8] reported an atypical GCT of the breast with clinical features of malignancy. This report concluded that high level Ki-67 alone was considered as a proof of malignancy.…”