'Malignant granular cell tumor of the Appendiceal orifice: a rare case and review of literature'

Abstract

Granular cell tumors (GCTs) are rare, mostly benign soft-tissue neoplasms, with only 8% occurring in the gastrointestinal tract, making the colon an uncommon location. We present the case of a 37-year-old Hispanic woman who underwent a screening colonoscopy due to a family history of colon cancer. A submucosal nodule at the appendiceal orifice was resected, and a biopsy revealed a malignant GCT, confirmed by S100-positive staining. The patient underwent a right hemicolectomy, with the resection showing a 2 mm focus of granular cell tumor with clear margins. Histopathology confirmed malignancy, with additional findings of reactive hyperplasia of mucosa-associated lymphoid tissue and focal ileitis. Although rare in the colon, malignant GCTs carry a high risk of mortality and recurrence. Small lesions (< 1 cm) can be monitored, but larger or malignant ones require surgical resection. Our case emphasizes the importance of early detection and intervention to prevent severe outcomes in malignant GCTs.

Keywords: appendix; case report; colonoscopy; granular cell tumor.

Figure 1

Colonoscopy showing nodule at appendiceal orifice.

Figure 2

Biopsy shows proliferation of bland round to ovoid cells with prominent eosinophilic, granular cytoplasm.

Figure 3

Immunostain shows cells are diffusely positive for S100.

Figure 4

Resection specimen shows focus of granular cell tumor involving mucosa and submucosa.