Pleomorphic hyalinized angiectatic tumor of soft parts

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

Pleomorphic hyalinizing angiectatic tumor (PHAT) of soft tissues is a rare, non-metastatic tumor of unknown etiology and uncertain behavior, which may recur locally. There are few reports on this condition, and due to the rarity of the disease, its lineage has not yet been fully elucidated. The present study aims to report the case of an unusual entity observed for the first time in vulval topography. A female patient, 83 years old, presented with a tumor in the vulvar region that had evolved for approximately 4 months. Magnetic resonance imaging showed an expansive perineal formation of 8.5 × 3.5 cm, and a hemivulvectomy with a flap rotation was performed. The review of the slides revealed a mesenchymal lesion without significant atypia, which was richly vascularized. In the areas of interest, the immunohistochemical (IHC) study demonstrated positivity for CD34, estrogen, and progesterone receptors; it was negative for the other tested markers. Morphological findings associated with the IHC staining panel supported the diagnosis of PHAT. The main morphological features of PHAT are clusters of ectatic vessels of different sizes that show deposits of subendothelial and intraluminal fibrin. Fusiform and pleomorphic cells randomly arranged in leaves or long fascicles intermingle these vessels. It is essential to recognize this entity and consider it among the differential diagnoses of a mesenchymal lesion, given the wide variety of entities that comprise this group of lesions.

The t(1;10)(p22;q24) TGFBR3/MGEA5 Translocation in Pleomorphic Hyalinizing Angiectatic Tumor, Myxoinflammatory Fibroblastic Sarcoma, and Hemosiderotic Fibrolipomatous Tumor

CONTEXT.—

Pleomorphic hyalinizing angiectatic tumor (PHAT) of soft parts, hemosiderotic fibrolipomatous tumor (HFLT), and myxoinflammatory fibroblastic sarcoma (MIFS) are 3 distinct entities of low-grade spindle cell mesenchymal neoplasm. These tumors have similar clinical presentations and partially overlapping but distinctive pathologic features. A recurrent translocation, t(1;10)(p22;q24), has been detected in a subset of PHAT, HFLT, MIFS, and HFLT/MIFS hybrid cases. Translocation t(1;10)(p22;q24) involves transforming growth factor β-receptor 3 ( TGFBR3) and meningioma-expressed antigen 5 ( MGEA5) genes on chromosomes 1p22 and 10q24, respectively. However, the percentage of translocation in PHAT, HFLT, and MIFS varies significantly among different studies. The relationship among these tumors has been a controversial topic among experts.

OBJECTIVE.—

To discuss the diagnostic and functional significance of translocation t(1;10)(p22;q24) TGFBR3/MGEA5 rearrangement in HFLT, PHAT, and MIFS.

DATA SOURCES.—

PubMed was used for this study.

CONCLUSIONS.—

Diagnosis of HFLT, PHAT, and MIFS is challenging because of a lack of unique morphologic, immunophenotypic, molecular, and cytogenetic markers. The recurrent t(1;10)(p22;q24) translocation and/or TGFBR3/MGEA5 rearrangement was reported in 55 patients, with a relatively even distribution among HFLT, PHAT, and MIFS (17 HFLT, 15 MIFS, 13 MIFS/HFLT, and 10 PHAT). This indicates that current morphology-based diagnostic criteria do not identify reliably the subset of soft tissue tumor with t(1;10) translocation. Genetic heterogeneity of these tumors is supported by the recent detection of a mutually exclusive, second recurrent genetic change, t(7;17) TOM1L2-BRAF translocation or BRAF amplification, in a subset of MIFS.

Early pleomorphic hyalinizing angiectatic tumor: precursor or distinct lesion?

Early pleomorphic hyalinizing angiectatic tumor is a rare and recently described soft tissue lesion. Originally believed to be a precursor lesion to neoplastic pleomorphic hyalinizing angiectatic tumor, and possibly identical to hemosiderotic fibrohistiocytic lipomatous lesion/tumor, there have been recent suggestions that it is distinct from pleomorphic hyalinizing angiectatic tumor and is instead a reactive process. This article reports a case of a mass in the foot of a 45-year-old woman, which is 1 of only 15 published cases of early pleomorphic hyalinizing angiectatic tumor and is the first case to describe its radiographic appearance. Early pleomorphic hyalinizing angiectatic tumor predominantly develops in the fourth to sixth decades (average age, 45 years, range, 10-67 years). Females predominate 4 to 1. The foot/ankle is the most common site (67%). On magnetic resonance imaging (MRI), the mass appeared inhomogeneously dark on T1-weighted sequences and inhomogeneously bright on fat-suppressed T2-weighted sequences. Forty-four percent of resected lesions recur locally, but no early pleomorphic hyalinizing angiectatic tumor lesion has ever metastasized. These clinical characteristics of early pleomorphic hyalinizing angiectatic tumors closely mirror those of hemosiderotic fibrohistiocytic lipomatous lesions/tumors and are dissimilar to those for classic pleomorphic hyalinizing angiectatic tumors. Therefore, although the 3 entities share several histologic features, we believe early pleomorphic hyalinizing angiectatic tumor is equivalent to hemosiderotic fibrohistiocytic lipomatous lesion/tumor and is not a true precursor to classic pleomorphic hyalinizing angiectatic tumor.

Pleomorphic Hyalinizing Angiectatic Tumor of Soft Parts: Ultrastructural Analysis of a Case with Original Features

Pleomorphic hyalinizing angiectatic tumor, a rare neoplasm of uncertain lineage resembling malignant fibrous histiocytoma and schwannoma, was first described in 1996 by M. E. F. Smith et al. (Am Surg Pathol. 20:21-29). To date, less than 100 cases have been reported in the international literature. It occurs in subcutaneous and intramuscular soft tissues of extremities or trunk in adults without sex predilection. All lesions are composed of sheets and fascicles of spindled and pleomorphic cells associated with clusters of thick-walled ectatic vessels surrounded by a perivascular hyaline material and inflammatory cells such as mast cells. About one-half of these neoplasms express CD34. No patient has developed metastases but occasional local recurrences are possible. This tumor of uncertain lineage is suggested to be an aggressive locally growing low-grade sarcoma. Only 3 cases were previously studied by electron microscopy and appeared to consist of primitive fibroblastic cells. The authors report histological and ultrastructural characteristics of a new case of PHAT excised from the right buttock of a 66-year-old man with the presence of ganglion-like cells, a feature that has not been previously reported, and unusual central ischemic necrosis. The features of this case are suggestive of a fibroblastic origin.

Pleomorphic hyalinizing angiectatic tumor with a sarcomatous component recurring as high-grade myxofibrosarcoma

Pleomorphic hyalinizing angiectatic tumor (PHAT) of the soft tissue is a rare distinctive tumor listed as a benign neoplasm in the new World Health Organization classification. It may recur and most reported recurrent tumors retained the typical morphological appearance of PHAT; rare tumors recurred with the appearance of a sarcoma. Reported herein is an additional example of recurrent PHAT, but in contrast to the previously described cases the present tumor morphologically qualified as a sarcoma from the very beginning; it recurred as a high-grade myxofibrosarcoma. A 76-year-old woman presented with a solitary subcutaneous tumor in the axilla that was surgically removed. Seven months later, the patient experienced a local recurrence. Microscopically, the typical features of PHAT were identified in the initial lesion, namely hyalinized, fibrin-containing vessels and pleomorphic stromal cells; there were areas of hemorrhage and necrosis. Additionally, peripherally located areas of the tumor manifested highly pleomorphic cells with frequent atypical mitoses, producing a sarcomatous appearance. The mitotic index in the sarcomatous part was 1/10 high-power fields (HPF). Hyalinized, fibrin-containing vessels were absent in these sarcomatous areas, and the stroma was myxoid. The recurrent lesion was composed of large highly pleomorphic oval, round, spindled or bizarre cells with a high mitotic rate, ranging from 3/10 HPF to 7/10 HPF. The neoplastic cells were arranged haphazardly in a myxoid matrix. Hyalinized, fibrin-containing vessels typical for PHAT were absent. PHAT may be more aggressive than previously thought, and PHAT may encompass a morphological spectrum of the lesion ranging from benign to malignant.

Hemosiderotic fibrohistiocytic lipomatous lesion: Early pleomorphic hyalinizing angiectatic tumor?

Hemosiderotic fibrohistiocytic lipomatous lesion (HFLL) and early pleomorphic hyalinizing angiectatic tumor (PHAT) are characterized histologically by an admixture of fat, moderately cellular fascicles of hemosiderin-laden spindle cells growing in a perivascular, periadipocytic and septal pattern, as well as the presence of macrophages and chronic inflammatory cells. In contrast to a suggested reactive nature of HFLL, PHAT is regarded as a non-metastasizing tumor of uncertain lineage in the recent World Health Organization classification of soft tissue tumors. Reported herein is the case of a 47-year-old woman with an unencapsulated and irregularly circumscribed recurring lesion in the ankle/foot region that developed following ankle distortion and that fulfills histological criteria for both HFLL and early PHAT. In summary, the present case suggests a reactive over-neoplastic nature of HFLL and confirms profound histological similarities with early PHAT. Until more data become available on the biological potential of HFLL/early PHAT, radical surgical excision and follow up of the patient remains the best treatment option.

Primary Cutaneous Myxofibrosarcoma Mimicking Pleomorphic Hyalinizing Angiectatic Tumor (PHAT)

Myxofibrosarcoma (MFS) is one of the most common sarcomas of adults, and includes lesions ranging from low to high grade based on increasing cellularity, nuclear pleomorphism, and mitotic activity. We present an unusual case of MFS, which initially showed features of a pleomorphic hyalinizing angiectatic tumor (PHAT), a rare soft-tissue tumor considered benign in the WHO classification. The initial lesion showed a subcutaneous proliferation of spindled to polygonal eosinophilic cells with striking cellular pleomorphism, set in a myxoid to sclerotic stroma with prominent hyalinized and angiectatic vasculature, classic characteristics of PHAT. Rare mitotic figures were identified. The preliminary diagnosis of PHAT was confirmed by a consultant expert soft-tissue pathologist. Four months after the initial surgery, local recurrence was noted. The recurrent tumor demonstrated findings of a high-grade MFS, with a diffuse and cellular proliferation of atypical spindle cells set in a prominent myxoid stroma. Multiple mitoses, including atypical ones, were present. In light of these findings, the original specimen was reexamined and the initial diagnosis was amended to MFS. MFS may mimic or be confused with several benign soft-tissue lesions. Cases mimicking PHAT have not been previously reported. We describe a unique case of a high-grade MFS that initially showed characteristic features of a PHAT, to illuminate the fact that MFS may rarely arise in, or have areas that masquerade as, PHAT. It is also conceivable, although speculative, that at least some cases of PHAT, currently considered a benign tumor by the WHO, may actually represent or evolve into a unique form of MFS of low malignant potential.

Fine-needle aspiration cytology of pleomorphic hyalinized angiectatic tumor: A case report

Pleomorphic hyalinized angiectatic tumor (PHAT) of soft parts is a neoplasm characterized by spindle and pleomorphic cells associated with an angiectatic vasculature. We describe the cytological findings of a fine-needle aspiration biopsy (FNAB) from the right medial knee of a 45-yr-old woman. The aspirate material was entirely submitted in Cytolit solution. The specimen was moderately cellular and was comprised of spindle cells in a background of fibrinous material. The cells varied from small, bland spindle cells with a fine chromatin pattern and inconspicuous nucleoli to larger pleomorphic cells with coarser chromatin and occasional intranuclear inclusions. Most of the cells were arranged singly with sporadic small cluster formation with indistinct cell borders. Rare mononuclear inflammatory cells morphologically compatible with mast cells were identified. The differential diagnosis include solitary fibrous tumor (SFT) and ancient schwannoma, which also shows fibrous-like material and spindle cells that may have intranuclear inclusions.

Pleomorphic Hyalinizing Angiectatic Tumor

The pleomorphic hyalinizing angiectatic tumor (PHAT) is a rare, low-grade neoplasm that features atypical stromal cells containing hemosiderin, partially thrombosed ectatic vessels with circumferential hyalinization, and a variable inflammatory infiltrate. Over the years, we have occasionally observed a monomorphic partially myxoid spindle cell component (provisionally termed "early PHAT") co-existing with classic PHAT. In some instances, this monomorphic lesion occurs by itself, suggesting an early stage in the evolution of PHAT. To explore this hypothesis and to better define the long-term behavior of PHAT, we have reviewed our experience with these lesions. Forty-one cases were identified from consultation files. They occurred chiefly in adults (median 51 years, range 10-79 years) of either sex (23 female, 18 male), ranged from 0.3 to 19.7 cm (median 5.6 cm), and involved the subcutis of the ankle/foot (N = 15), leg (N = 10), thigh (N = 6), and other sites. Thirteen tumors had been present for more than 1 year prior to biopsy. Fifteen tumors consisted entirely of typical PHAT. Twelve cases conformed to "early PHAT," lacked fully developed features of PHAT, and showed instead short fascicles of hemosiderin-stippled spindled cells that infiltrated fat and surrounded congeries of small, damaged vessels. With close scrutiny, all contained rare pleomorphic cells with intranuclear pseudo-inclusions, as seen in typical PHAT. Fourteen cases contained both classic and early PHAT, in variable proportions. Follow-up was available in 18 patients (mean 84 months, median 52 months; range 13-420 months). Six of 18 patients developed recurrences, 1 with classic PHAT, 1 with mixed early-classic PHAT, and 4 with early PHAT. Following resection, 16 are disease free and 2 have persistent disease. None has developed metastasis. Based on the histologic overlap between early and classic PHAT, the presence of early PHAT at the periphery of classic PHAT, and the admixture of both patterns within the same tumor, we conclude that early PHAT represents a precursor lesion for PHAT. It appears essentially identical to the lesion termed "hemosiderotic fibrohistiocytic lipomatous lesion," supporting the notion that the latter is a neoplastic rather than a reactive lesion. PHAT should be considered mesenchymal tumors of intermediate malignancy, given their high rate of (sometimes aggressive) local recurrence.