Morphological and immunohistochemical characterization of granular cells in non‐hypophyseal tumours of the central nervous system

Abstract

We report 14 biopsy cases of granular cell tumours (GCT) of the central nervous system (CNS) outside the pituitary gland. In six cases the granular cells determined the morphology (actual GCT), the other eight consisted of different CNS tumours with a varying granular cell component. Pronounced immunoreactivity for ubiquitin and alpha-1-antichymotrypsin could be found in all investigated tumours, while GFAP, neuron specific enolase, von Willebrand factor, vimentin, S-100 protein, alpha-1-antitrypsin, actin, and the neurofilaments 68 kDa and 160 kDa showed mostly weak positivity in some cases. Four out of eight GCT showed no immunoreactivity for MIB1; the other four cases had a proliferation index between 0.5% and 15%. Six out of nine cases were positive for p53. We consider granular cells to originate from different cell types. Thus, although morphologically identical, GCT are actually biologically heterogeneous. GCT of the CNS may represent gliomas of mostly astrocytic origin with a metabolically induced transformation of some tumour cells into granular cells.

Intracranial Granular Cell Tumor in a Dog

“…These had heterogenous contents including round to irregular electron dense structures, finely granular material and vacuoles, presumably phagolysosomes that contained cell debris or cytoplasmic constitutents (Fig. 6), as reported previously in animals and humans [3,5,13,16,19].…”

“…In cats, GCT has been reported in the tonsil, tongue, vulva, and digits [3,14]. Human GCT is most commonly located in the tongue and subcutaneous tissue, but various sites may be involved including neurohypophysis or infundibulum [5,7,12,16,18,19]. Other reports of GCT in animals included those in the maxillary mucosa in a cockatiel [14] and in the medial portion of the right forebrain in a ferret [17].…”

“…Five cases of GCT in the CNS have been reported in dogs since 1978, and the locations included the parieto-occipital cortex, olfactory bulb, frontal cortex and pituitary gland [1,5,6,13]. GCT is generally considered to be benign [16], with slow progression and lack of invasive growth [19]. However, an infiltrative and expansible growth compressing adjacent cerebral neuroparenchyma may be responsible for the development of neurological signs in this case.…”

“…Initially, these tumors were believed to be of skeletal muscle origin and called granular cell myeloblastoma [14]. Most human intracranial GCTs from neurohypophysis are considered to be derived from specialized pituicytes or to originate from Schwann cells or astrocytes [16,19]. In rats, GCTs are located in or adjacent to the meninges of the cranial cavity, and the histogenesis has been regarded as a progenitor meningiothelial arachnoid cell because of their anatomic location, and immunohistochemical and/or electron microscopic features [10,11,20].…”

Granular Cell Tumor in a Lumbar Spinal Nerve of a Dog

“…"content-markup(./author-grp [1]/aff|./author-grp [1]/dept-list)> Granular cell tumors (GCTs) are uncommon, nonaggressive mass lesions. 22,33 For a time, it was unclear whether these masses were a reactive cellular response or true neoplasms. However, because these masses do rarely metastasize, it is accepted that GCTs are neoplasms.…”