Pleomorphic Hyalinizing Angiectatic Tumor (PHAT): Review of the Literature with Case Presentation

Abstract

Pleomorphic hyalinizing angiectatic tumor (PHAT) is a very rare entity of soft tissue considered a “neoplasm of uncertain behaviour of connective or other soft tissue” by the World Health Organization (2020). It develops in subcutaneous tissue of the lower extremities, more frequently in the region of the ankle and foot, and rarely as a deep-seated soft tissue mass in locations such as the perineum, buttock, arms, head and neck, and viscera. Although inconsistent cytogenetic data have been reported on PHAT so far, there are potential morphological and genetic overlaps with hemosiderotic fibrolipomatous tumor (HFLT) and myxoinflammatory fibroblastic sarcoma (MIFS). Here we report a case of PHAT at the level of the upper third of the right thigh in a 48-year-old patient and we also focus on the differential diagnoses of these entities and conduct a literature review of reported cases.

Pleomorphic hyalinizing angiectatic tumor of the vulva: literature review based on a rare presentation

“…1 The World Health Organization (WHO) defines the condition as "very rare," with around 100 cases reported in the world literature. 5,6 There are references in articles that described PHAT in other topographies, which include the trunk, upper extremities, axilla, inguinal region, perineum, buttocks, back, oral cavity, and scrotum. 5,7 In a systematic search using the PubMed search tool, 52 articles that allude to PHAT were found in 118 reported cases (Table 1).…”

“…5,6 There are references in articles that described PHAT in other topographies, which include the trunk, upper extremities, axilla, inguinal region, perineum, buttocks, back, oral cavity, and scrotum. 5,7 In a systematic search using the PubMed search tool, 52 articles that allude to PHAT were found in 118 reported cases (Table 1). To date, this is the first case of PHAT described in the vulvar region.…”

“…The clinical behavior of PHAT is characterized by local recurrence in up to 50% of cases, but metastases have not been documented to date. [2][3][4][5] Local excision with wide margins is recommended as the best therapeutic approach whenever possible, as this tumor has a local recurrence rate of around 33%. 4,6,7 There is no relevant evidence for the role of adjuvant therapy in PHAT.…”

“…4,6,7 There is no relevant evidence for the role of adjuvant therapy in PHAT. 5,7 Adjuvant radiotherapy has been used in some case series to reduce the rate of local recurrence, but more evidence is needed before indicating its use, and chemotherapy is not useful in view of the absence of metastases. 5,7 Since its original morphological description, attention has focused on the lesion's striking vascular patterns, distinguishing PHAT from other mesenchymal lesions.…”

“…5,7 Adjuvant radiotherapy has been used in some case series to reduce the rate of local recurrence, but more evidence is needed before indicating its use, and chemotherapy is not useful in view of the absence of metastases. 5,7 Since its original morphological description, attention has focused on the lesion's striking vascular patterns, distinguishing PHAT from other mesenchymal lesions. 4 PHAT is characterized by dilated blood vessels with prominent circumferential hyalinization; it is surrounded by a cell proliferation composed of spindleshaped and pleomorphic cells, some with hemosiderin, a low mitotic index, and variable inflammatory component.…”