Pleomorphic Hyalinizing Angiectatic Tumor of Soft Parts

Abstract

Pleomorphic hyalinizing angiectatic tumor (PHAT) of soft parts is a rare, nonmetastasizing tumor of uncertain lineage which was first reported in 1996. Here, we report a case of PHAT and review the literature. A 49-year-old man presented with a soft and progressively enlarging mass over the right buttock for several years. On suspicion that the mass was a right gluteal lipoma, he underwent surgical excision. The excised lesion measured 14 x 6 x 3.5 cm. It had a variegated appearance with a white-tan to yellowish color on the cut surface. Some punctate hemorrhage and vessel thrombosis were seen. Microscopically, the tumor was a PHAT characterized by clusters of ectatic, fibrin-lined, thin-walled vessels, which were surrounded by a mitotically inert, spindled, pleomorphic, neoplastic stroma that contained a variable inflammatory component. Immunohistochemical study showed that the tumor cells were positive for CD34, and negative for S-100, HMB45 and actin. The patient experienced local recurrence 6 months later. The recurrent tumor was widely excised. No evidence of metastasis was found during the 18 months after the second operation. The recurrent lesion had a microscopic appearance that was similar to the initial lesion.

A case of a pleomorphic hyalinizing angiectatic tumor of soft parts with intracytoplasmic hemosiderin pigment apparent upon fine‐needle aspiration cytology

“…The tumor demarcation in the present case may be related to marked intratumoral hemorrhage, which may in turn be derived from vascular permeability induced by intratumoral mast‐cell products . Among the previously reported macroscopically demarcated PHATs, five were described as having a microscopic infiltrative border, but no satellite lesions were found. The pathogenesis of the satellite lesions remains unclear at present.…”

“…Smith et al reported that PHATs usually have an infiltrative margin, and Folpe and Weiss also demonstrated infiltrative growth in all cases of PHAT. However, further cases of demarcated PHAT have been reported, and among those in which the tumor's macroscopic appearance was described, 25 had an infiltrative margin and 16 had a demarcated margin. The tumor demarcation in the present case may be related to marked intratumoral hemorrhage, which may in turn be derived from vascular permeability induced by intratumoral mast‐cell products .…”

Comprehensive clinical and pathological analysis of three rare vascular tumor cases

“…The disease was mainly found in the trunk, limbs and subcutaneous tissue of lower limbs in adult women. It generally appeared as a mass of slow growth (18). The histological features were thin-walled and expanded blood vessels that were distributed in clusters; the walls and matrix transparently degenerated and residual pleomorphic tumor was visible among blood vessels with the split as low as <1/50 HPF.…”

Features of Glucose Metabolism in Pleomorphic Hyalinizing Angiectatic Tumor (PHAT)

“…PHAT describes a heterogeneous group of neoplasms of undetermined tumorigenesis, characterized by clusters of ectatic, fibrinlined, and thin-walled vessels that are surrounded by spindled or pleomorphic neoplastic cells with variable inflammatory components. The neoplastic cells frequently have intracytoplasmic hemosiderin granules, intranuclear inclusions, and low mitotic activity [2][3][4][5]. Based only on the morphological findings of histopathology, the biological potential of the tumor is indeterminate.…”

“…The proliferative spindle cells of the neurofibroma and the intense inflammation associated with the granuloma were considered to have contributed to the increased FDG uptake (SUVm = 4.6 and 10.8, respectively) in those cases. Only one previous case of PHAT had been found at our institution [3], and that tumor had displayed mild FDG uptake (SUVm = 1.4) during FDG-PET examination. In PHAT, we propose that FDG accumulation in the ectatic vessel, increased uptake of the pleomorphic cells and/or associated inflammatory cells, and increased permeability of the stroma lead to the imaging feature.…”