Pleomorphic Hyalinizing Angiectatic Tumour: A Rare Case Report and Discussion of Differential Diagnosis

Abstract

A 50-year-old man presented with a solitary, slow growing mass in the left calf region since two years. The patient gave history of rapid increase in size of the swelling since two months following thorn injury. Magnetic Resonance Imaging (MRI) revealed a large well defined lobulating heterogenous soft tissue malignant neoplasm arising from posteromedial aspect of gastrocnemius muscle extending into subcutaneous plane. Fine Needle Aspiration Cytology (FNAC) of the swelling revealed a low cellular smear with bland spindle shaped cells having moderate amount of cytoplasm, elongated nuclei and inconspicuous nucleoli admixed with anastomosing capillary network and few mature adipocytes in a haemorrhagic background. Based on these findings differential diagnosis of haemangioma or angiolipoma were given.Wide surgical excision of the mass was done and sent for histopathological evaluation. Grossly, the mass measured 13.5 x 12 x 6 cm with an ulcer on the skin surface measuring 6 x 5 cm. On cut surface, circumscribed, firm mass was noted measuring 9 x 5.5 cm, which was predominantly solid having lobulated appearance. Also, seen many blood filled cystic spaces of varying sizes [Table/ Fig-1,2].Microscopically, the lesion was unencapsulated with vascular and cellular areas. Cellularity was variable and it was composed of hyper and hypocellular areas. The tumour tissue in the hyper cellular areas predominantly comprised of spindle shaped cells arranged in interlacing bundles and fascicles, with round to oval vesicular nuclei, inconspicuous nucleoli and moderate amount of eosinophilic cytoplasm. Few pleomorphic cells having vesicular single or multilobated nucleus with prominent nucleoli and abundant eosinophilic cytoplasm were also noted. Few cells showed intranuclear inclusions. Many multinucleated giant cells were also noted. Hypocellular areas were comprised of spindle shaped cells with round to oval nuclei having fine nuclear chromatin and moderate amount of eosinophilic cytoplasm and were dispersed in a myxoid background. These tumour cells were infiltrating the adjacent adipose tissue focally. The vascular areas were comprised of many, large clusters of ectatic thin walled blood vessels. Subendothelial fibrin deposition, organized luminal thrombus and perivascular hyalinization were noted in majority of the vessels. AbStRACtPleomorphic Hyalinizing Angiectatic Tumour (PHAT) is one of the rare soft tissue tumour which is non-metastasizing. The origin of this tumour is yet uncertain. It occurs in adults as a slow growing subcutaneous mass mimicking clinically and histologically to various benign and malignant soft tissue tumours such as schwannoma, haemangioma and malignant fibrous histiocytoma. The microscopic features of this tumour include clusters of ectatic, fibrin containing, hyalinized blood vessels with pleomorphic and spindle shaped tumour cells showing intranuclear inclusions, stromal haemosiderin pigment and a variable inflammatory infiltrate. Despite marked pleomorphism, the lesion behaves as a low grade neo...

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

“…1,60 PHAT shares morphological characteristics with SFT and giant cell angiofibroma. 1,19,34,59 Nuclear atypia found in PHAT are more prominent than those seen in SFT, and the presence of multinucleated giant cells is seen only in PHAT. 1,19,34,59 Prominent clusters of thin-walled ectatic vessels surrounded by perivascular hyaline material are characteristic in PHAT, but may also be present in solitary fibrous tumors and giant cell angiofibromas, and may correspond to secondary changes due to circulation disorders often seen in tumors of slow growth.…”

“…61 The main differential diagnoses found in the searches are schwannoma, pleomorphic sarcomas (formerly called malignant fibrous histiocytoma), s o l i t a r y f i b r o u s t u m o r ( S F T ) a n d g i a n t c e l l angiofibroma. 1,18,19,34,62,63 Tumor cells resemble those of pleomorphic sarcomas, but differ from them by the presence of prominent intranuclear cytoplasmic pseudoinclusions, the scarcity of mitotic figures, and the frequent presence of CD34 expression. 1,59 These tumors also share several characteristics with schwannomas, such as their hyalinized vessel wall, intranuclear cytoplasmic inclusions, very low mitotic activity, and the presence of mast cells; however, they are differentiated by the frequent presence of infiltrating margins and the absence of S-100 protein labeling.…”

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

“…The average dimensions were around 5.3 cm, with an exceptional case of 26.3 cm in male breast reported by Lee et al in 2005 [ 16 ]. Interestingly, Wei et al [ 26 ] and Chalmeti et al [ 35 ] reported two cases of PHAT respectively at the level of the renal hilum and within the kidney itself, emphasizing the potential problem of confusing this entity with other neoplasms of kidney. Our data completely agrees with Rush et al [ 41 ], who in a recent article in 2018 conducted a detailed review of the literature more focused on the surgical-oncological implications related to PHAT.…”

“…In most of cases it has a lobulated appearance, with a gray to light brown cut surface. It is never encapsulated, and many of these lesions have diffusely infiltrative edges, although well-defined margins [ 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 ]. Sometimes, PHAT can have a prominent cystic component [ 16 , 17 , 18 , 19 ].…”

“…Wei et al [ 26 ] described the presence of unbalanced translocations involving chromosomes 1 and 3 and chromosomes 1 and 10 mapped to TGFBR3 and/or OGA (MGEA5) and in other related neoplasms such as myxoinflammatory fibroblastic sarcoma (MIFS): this feature led to the hypothesis that the origin of these tumors was similar and that neoplasms such as MIFS had acquired greater aggressiveness than PHAT and HFLT [ 30 , 41 ]. In spite of the small number of cases, this finding should be considered when following these patients and most importantly if a recurrence occurs [ 2 , 35 , 36 ].…”