Granular Cell Tumor, Gastrointestinal

Synonyms

Abrikossoff tumor; Granular cell myoblastoma; Granular cell nerve sheath tumor; Granular cell schwannoma

Definition

Granular cell tumors comprise a group of variable etiological and clinical tumors characterized by large cells with granular eosinophilic cytoplasm. Myoblasts, Schwann cells, histiocytes, perineural fibroblasts, and undifferentiated mesenchymal cells have been postulated as the origin of the tumor, while theories of the nonneoplastic nature of the lesion resulting from trauma, as a degenerative process or as a storage disorder involving histiocytes, have also been claimed. Recent reports support a peripheral nerve-related cell of origin for the majority of these tumors based on the findings of cytoplasmic granules with numerous membrane-bound vacuoles containing myelin-like tubules and “angulate bodies” that show close relation with preexistent axons at the ultrastructural level, found between granular cells. The expression of nestin in granular cell tumors...