Molecular pathology of hemangiopericytomas accompanied by severe hypoglycemia: oncogenes, tumor-suppressor genes and the insulin-like growth factor family

Clinical and histopathological findings of a rare sinonasal glomangiopericytoma

Glomangiopericytoma is a rare vascular neoplasm of the nasal cavity and paranasal sinuses that occurs during the sixth or seventh decade of life. It is categorized as a borderline tumor with low malignant potential and classified as a distinct entity of sinonasal tumors with perivascular myoid phenotype by the World Health Organization (WHO). We report the case of a 50-year-old woman with nasal obstruction and severe epistaxis. The nasal sinuses computed tomography (CT), and magnetic resonance imaging (MRI) demonstrated a 3.1 cm soft tissue mass occupying the upper part of the left nasal cavity invading the left paranasal sinuses and nasal septum, and the left eye medial rectus muscle. A total mass resection was performed by nasal endoscopy. The histological and immunohistochemical examination yielded the diagnosis of glomangiopericytoma. This case report aims to contribute to the knowledge of nasal neoplasms. The need for more data on this entity is the main obstacle to developing standardized treatment guidelines.

A novel mouse model of hemangiopericytoma due to loss of Tsc2

Hemangiopericytoma (HPC) is a rare vascular tumor, which is thought to originate from pericytes. However, no direct evidence for the cell of origin has been found, and the mechanism of HPC tumorigenesis is poorly understood. Here we report that loss of the tumor suppressor gene Tsc2 in pericytes using a FoxD1 promoter driven cre allele (Foxd1tm1(GFP/cre) Amc, FoxD1GC) leads to the formation of HPC in multiple sites. Tsc2ffFoxD1GC mice had stunted growth with seizures and tail and hind limb tremor with a median survival of 110 days. They also showed recombination in brain, spinal cord, tongue, liver, intestine and skeletal muscle. Distinctive perivascular tumors consisting of cells with oval nuclei and scant cytoplasm were identified in multiple sites in all Tsc2ffFoxD1GC mice. Immunohistochemistry staining showed a high expression of phospho-S6-S240/244, a hallmark of activated mTORC1, as well as pericyte markers NG2 and vimentin in these tumors. In summary, we demonstrate that loss of Tsc2 in pericytes generates HPC, the first mouse model of HPC reported.

A case of haemangiopericytoma-associated hypoglycaemia: Beneficial effect of treatment with radiotherapy

A 72-year-old lady presented with recurrent hypoglycaemia and a large pelvic mass. Hypoglycaemia was accompanied by undetectable serum insulin and c-peptide and high insulin-like growth factor II (IGFII) to IGFI ratio. She had undergone successful resection of a large bladder haemangiopericytoma 7 years earlier. A core biopsy was performed, and histology confirmed the recurrence of the haemangiopericytoma. Local palliative radiotherapy resulted in the reduction of IGFII level and IGFII to IGFI ratio and increased insulin, c-peptide and growth hormone (GH) level with long-term amelioration of hypoglycaemic episodes. Clinically and biochemically, radiotherapy was more effective than GH therapy.

Sinonasal-type hemangiopericytoma: a clinicopathologic and immunophenotypic analysis of 104 cases showing perivascular myoid differentiation

Sinonasal-type hemangiopericytoma is an uncommon upper aerodigestive tract tumor of uncertain cellular differentiation. We report 104 cases of sinonasal-type hemangiopericytoma diagnosed between 1970 and 1995 from the files of the Armed Forces Institute of Pathology. There were 57 females and 47 males ranging in age from 5 to 86 years (mean 62.6 years). The most common clinical presentation was airway obstruction (n = 57) and/or epistaxis (n = 54), with symptoms averaging 10 months in duration. The tumors involved the nasal cavity alone (n = 47) or also a paranasal sinus (n = 26), were polypoid, and measured an average of 3.1 cm. Histologically, the tumors were submucosal and unencapsulated and showed a diffuse growth with fascicular (n = 37) to solid (n = 50) to focally whorled (n = 7) patterns. The tumor cells were uniform in appearance with minimal pleomorphism and had spindle-shaped (n = 82) to round/oval (n = 18) nuclei with vesicular to hyperchromatic chromatin and eosinophilic to amphophilic to clear-appearing cytoplasm with indistinct cell borders. Multinucleated (tumor) giant cells were identified in a minority of cases (n = 5). Mitotic figures were inconspicuous and necrosis was absent. The tumors were richly vascularized, including staghorn-appearing vessels that characteristically had prominent perivascular hyalinization (n = 92). An associated inflammatory cell infiltrate that included mast cells and eosinophils was noted in the majority of cases (n = 87). The immunohistochemical profile included reactivity with vimentin (98%), smooth muscle actin (92%), muscle specific actin (77%), factor XIIIa (78%), and laminin (52%). Surgery was the treatment of choice for all of the patients; adjunctive radiotherapy was given to four patients. Recurrences developed in 18 patients within 1-12 years from diagnosis. Ninety-seven patients were either alive (n = 51, mean 16.5 years) or dead (n = 46, mean 9.6 years) but free of disease. Four patients had disease at the last follow-up: three died with disease (mean 3.6 years) and one patient is alive with disease (28.3 years). Recurrent tumor (17.8%) can be managed by additional surgery. The majority of sinonasal-type hemangiopericytomas behave in a benign manner with excellent long-term prognosis (88% raw 5-year survival) following surgery alone. Sinonasal-type hemangiopericytomas have a characteristic light microscopic appearance with an immunophenotypic profile resembling that of glomus tumors.