Rare Malignant Transformation of a Granular Cell Tumor: A Case of Recurrent Perianal Lesion With Pulmonary and Lymph Node Metastases

Abstract

This report presents the case of a 52-year-old woman with a recurrent perianal mass, initially diagnosed as a benign GCT. Despite surgical resection, the tumor later metastasized to the lungs and lymph nodes, indicating malignant transformation. Imaging and histological analysis confirmed the malignancy, with cellular atypia and metastasis. The patient declined further treatment and passed away shortly thereafter. This case underscores the potential for malignant transformation in GCTs, particularly in recurrent cases. While surgical removal with clear margins remains the standard approach, malignant GCTs often present a poor prognosis due to high rates of recurrence and metastasis, with limited response to chemotherapy and radiation therapy.

Keywords: abrikossoff tumor; granular cell tumor; lymph node metastases; neurogenic schwannian neoplasms; pulmonary metastases.

Figure 1. Sagittal section of a pelvic MRI

Arrow points to the mass infiltrating the ischiopubic fossa with irregular contours, poorly defined, invading the levator ani muscle, measuring 70x62 mm.

Figure 2. A. Microscopic image showing a proliferation of sheets and ribbons of cells separated by fine bands of collagen (HE, x200). B. Higher magnification microscopic image showing polygonal cells with small, dense nuclei. The cytoplasm is abundant and eosinophilic with coarse granules (HE, x400).

Figure 3. Frontal view showing swelling of the left para-anal region pushing the anus and narrowing the anal canal lumen.

Figure 4. Cross-sectional image of a chest CT scan

Arrow indicates multiple round opacities disseminated in both lung fields.