Hemosiderotic Fibrolipomatous Tumor, Pleomorphic Hyalinizing Angiectatic Tumor, and Myxoinflammatory Fibroblastic Sarcoma: Related or Not?

Myxoinflammatory Fibroblastic Sarcoma

MIFS is a low-grade fibroblastic sarcoma that predilects to superficial distal extremity soft tissue. It is composed of plump spindled and epithelioid cells, inflammatory infiltrates, and mucin deposits in a fibrosclerotic stroma. Large epithelioid cells harboring bizarre nuclei and virocyte-like macronucleoli and pleomorphic pseudolipoblasts are characteristic. While conventional MIFS has locally recurrent potential but minimal metastatic risk, tumors with high-grade histologic features have a greater risk for recurrence and metastasis. Wide local excision is the recommended treatment.

Recent Advances in the Diagnosis, Pathogenesis, and Management of Myxoinflammatory Fibroblastic Sarcoma

Myxoinflammatory fibroblastic sarcoma (MIFS) is an infiltrative, locally aggressive fibroblastic neoplasm of intermediate malignancy that typically arises in the distal extremities of middle-aged adults. It can histologically be confused with a number of benign and malignant conditions. Recently, high-grade examples of MIFS have been described. Immunohistochemistry plays a very limited role in the diagnosis of MIFS. Several genetic alterations have been identified in MIFS, including a t(1;10)(p22;q24) translocation with TGFBR3 and/or OGA rearrangements, BRAF rearrangement, and VGLL3 amplification. Although it appears that VGLL3 amplification is the most consistent alteration, the molecular pathogenesis of MIFS remains poorly understood. A wide resection is considered the standard treatment for MIFS. Radiotherapy may be a viable option in cases with inadequate surgical margins or cases where surgery is likely to cause significant functional impairment. The systemic treatment options for advanced or metastatic disease are very limited. This review provides an updated overview of the clinicoradiological features, pathogenesis, histopathology, and treatment of MIFS.

Pleomorphic hyalinizing angiectatic tumor: FNA analysis of a rare entity and review of the literature

INTRODUCTION

The fine-needle aspiration (FNA) cytopathology of pleomorphic hyalinizing angiectatic tumor (PHAT) is the subject of a very limited number of reports. We undertook a review of our FNA experience with this neoplasm.

MATERIALS AND METHODS

A search was made of our files for PHAT FNA cases with histopathologic confirmation. FNA biopsy smears and cell blocks were performed and examined using standard techniques.

RESULTS

Two primary cases of histologically proven PHAT [both male, ages 56 and 60 years] met study inclusion. FNA sites included buttock and foot. A misdiagnosis of sarcoma was made in each case. Ancillary immunohistochemical testing performed in 1 case suggested angiosarcoma. Cytologic smears showed only modest cellularity with a dual population of bland spindle cells and isolated large pleomorphic cells, many harboring nuclear pseudoinclusions. Smear background was clean, and mitoses absent.

CONCLUSIONS

The imitative cytopathology of PHAT with a pleomorphic sarcoma remains a pitfall in FNA specimens. Awareness of this entity and its lack of hypercellularity, necrosis, and cohesive groups of atypical cells in smears should assist the cytopathologist in avoiding a misdiagnosis of malignancy.

Benign Hand Tumors (Part II): Soft Tissue Tumors

Background: Benign soft-tissue tumors of the hand are more common than both their benign bone and malignant soft-tissue counterparts. This study evaluates the characteristics and treatment of benign soft tissue tumors in light of 1 institution's experience. Methods: Histologically confirmed benign soft-tissue tumors of the hand were retrospectively identified using International Classification of Disease codes from 1992 to 2015. A medical chart review was conducted to collect patient demographics, tumor epidemiology, and treatment. Results: A total of 199 soft-tissue tumors were identified. The median patient age at time of treatment was 47.4 ± 14.7 years in age. The majority of tumors were located in the digits (n = 168, 84%) and treated by excision (n = 191, 96%). Localized type tenosynovial giant cell tumors (n = 71, 36%) were the most common and had the highest rates of recurrence (8.5%) in this series. Other frequent histologies included hemangioma, schwannoma, and glomus tumors. Conclusion: Awareness and understanding of tumor characteristics may help physicians with diagnosis and treatment. There is an extensive variety of tumors, but the principles of clinical and imaging diagnosis are common to all of them. Marginal excision for the treatment pain, improvement of function, and cosmetic correction applies to all these tumors independent of the histology.

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.

Cytopathology of myxoinflammatory fibroblastic sarcoma: a series of eight cases and review of the literature

INTRODUCTION

Myxoinflammatory fibroblastic sarcoma (MIFS) is a rare low-grade sarcoma presenting as a slow-growing mass that occurs mainly in the distal extremities of adults. Relatively little is known about the cytopathology of MIFS. We evaluated cytologic characteristics of MIFS on fine-needle aspiration (FNA).

MATERIALS AND METHODS

A search was made of our cytopathology and surgical pathology databases for cases diagnosed as MIFS. FNA biopsy smears and cell-block were performed and examined using standard technique.

RESULTS

Eight cases were retrieved from patients aged 22-90 years (mean, 56 years), and M:F ratio of 1:1. Six tumors (75%) were primary, and 2 (25%) locally recurrent. Distal lower limb was involved in all but one case (88%). One (13%) recurrent case was correctly diagnosed cytologically as MIFS; remaining single diagnoses were varied: myxofibrosarcoma, low-grade sarcoma, malignant neoplasm, myxoid neoplasm, atypical fibrohistiocytic neoplasm, atypical cells with chronic inflammation, and spindle cells with atypia. Among 7 cases with available cytologic slides for review, common features were spindle cells with variable atypia (100%), rare virocyte/Reed-Sternberg -like cells (86%), background mixed inflammation (71%), and variable myxoid stroma (57%). Pseudolipoblasts and multinucleated giant cells were rare. Hemosiderin and branching capillaries were largely absent. Immunohistochemistry was non-specific.

CONCLUSION

MIFS was accurately interpreted in only 13% of cases; remaining cases were diagnosed as atypical or malignant, which would lead to proper management. A specific cytologic diagnosis of MIFS using FNA is extremely difficult in our experience due to an absence of distinctive cytomorphology and specific immunophenotype.

Recent updates in the diagnosis of soft tissue tumors: Newly described tumor entities, newer immunohistochemical and genetic markers, concepts, including "inter-tumor relationships"

During the last two decades, there have been significant strides in the diagnosis of soft tissue tumors, including identification of various tumor entities, newer immunohistochemical markers, and an increasing number of molecular signatures, defining certain tumors. Lately, there are certain emerging tumor entities, defined by their molecular features with an impact on treatment. At the same time, there is a certain degree of overlap in the expression of certain immunohistochemical antibody markers, as well as genetic markers, with certain gene rearrangements and chimeric fusions observed among completely different tumors. Moreover, a certain amount of clinicopathological, immunohistochemical, and molecular proximity has been unraveled among certain tumor types. Over the years, the World Health Organization (WHO) fascicles on tumors of soft tissue have succinctly brought out these aspects. The present review describes recent updates in the diagnosis of soft tissue tumors, including certain newly described tumor entities; emphasizing upon newer, specific immunohistochemical and molecular markers, along with concepts, regarding "intertumor relationships".

Myxoinflammatory fibroblastic sarcoma: an immunohistochemical and molecular genetic study of 73 cases

Myxoinflammatory fibroblastic sarcoma (MIFS) is a rare, low-grade soft tissue neoplasm preferentially arising in the extremities of young to middle-aged adults characterized histologically by a variegated appearance and absence of a distinctive immunophenotype. Herein we have evaluated a series of 73 cases of MIFS to define potential features and markers that may facilitate diagnosis. An immunohistochemical study with a large panel of antibodies showed strong positivity of the tumor cells for bcl-1 (94.5%), FXIIIa (89%), CD10 (80%), and D2-40 (56%). FISH and array comparative genomic hybridization (aCGH) were performed in a large subset of cases to investigate the utility for detecting the TGFBR3 and OGA t(1;10) rearrangement and BRAF abnormalities. Using a combination of FISH and/or aCGH, t(1;10) was detected in only 3 of 54 cases (5.5%). The aCGH study also demonstrated amplification of VGLL3 on chromosome 3 that was detected in 8 of 20 cases (40%). BRAF alterations were observed by FISH in 4 of 70 cases (5.7%) and correlated with gain of chromosome 3p12 (VGLL3). A novel fusion transcript involving exon 6 of ZNF335 and exon 10 of BRAF was identified in one case. Demonstration of amplification of VGLL3 on chromosome 3 in combination with expression of bcl-1 and FXIIIa may help support the diagnosis, however, due to their low specificity these markers are not sufficient for a definitive diagnosis in the absence of the appropriate clinical-pathological context. Until a more robust genetic or immunohistochemical signature is identified, the diagnosis of MIFS rests on its characteristic clinicopathological features.

High FDG Uptake in Pleomorphic Hyalinizing Angiectatic Tumor

PHAT (pleomorphic hyalinizing angiectatic tumor) is a rare, locally aggressive, low-grade mesenchymal neoplasm of uncertain lineage with a predilection for the lower extremities. We report a 74-year-old woman with an enlarging mass on the right popliteal fossa undergoing FDG PET/CT to characterize its biological activity. Increased accumulation of FDG (SUVmax, 23.0) in the solid component of the tumor was seen. Diagnosis of PHAT was confirmed by examination of the surgical resection specimens. This case showed significant FDG accumulation relative to its pathological low-grade malignant nature.

"Pauci-Hemosiderotic" Fibrolipomatous Tumor: A Mimicker of Various Lipomatous Lesions

Hemosiderotic fibrolipomatous tumor is a rare soft tissue tumor that preferentially affects the dorsum of foot, shows recurrent t(1;10) translocation targeting TGFBR3 and OGA (MGEA5) genes, and has a high recurrence potential. Hemosiderin deposits, mature adipocytes, and interspersed spindle cells are the 3 cardinal morphologic features of this tumor. We describe a "pauci-hemosiderotic" example involving the left wrist of a 45-year-old female, posing a diagnostic pitfall. The tumor comprised mature adipose tissue traversed by variably thick fibrous septa containing short fascicles of spindle cells. Prominent small- to medium-sized blood vessels were present, often with perivascular fibrosis or aggregates of foamy histiocytes, sometimes associated with red cell extravasation. Hemosiderin was not conspicuous, but fine deposits could be found focally on careful search and with the aid of Perls stain. The diagnosis was further confirmed by diffuse expression of CD34 and presence of OGA translocation by fluorescence in situ hybridization. Pathologists should be aware that hemosiderin deposition can be scanty and focal in hemosiderotic fibrolipomatous, but the rich vasculature with a "damaged" appearance is a useful diagnostic clue.

Epithelioid Cutaneous Mesenchymal Neoplasms: A Practical Diagnostic Approach

Epithelioid cells are rounded or polygonal cells with abundant eosinophilic or clear cytoplasm and ovoid to round nuclei, superficially resembling epithelial cells. Cutaneous mesenchymal neoplasms composed predominantly or exclusively of epithelioid cells are relatively uncommon and can cause considerable diagnostic difficulties due to overlapping histologic features among heterogeneous groups of tumors. Familiarity with practical diagnostic approaches and recognition of key histopathologic features are important for correct diagnosis and management. This review summarizes the histologic features of epithelioid cutaneous mesenchymal neoplasms and discusses their differential diagnoses from malignant melanomas and carcinomas.

Targeted RNA-sequencing identifies FBXW4 instead of MGEA5 as fusion partner of TGFBR3 in pleomorphic hyalinizing angiectatic tumor

Pleomorphic hyalinizing angiectatic tumor (PHAT) is a rare mesenchymal tumor of intermediate malignancy. PHAT, and the related hemosiderotic fibrolipomatous tumor, show a recurrent t(1;10)(p22;q24). Fluorescence in situ hybridization (FISH) and BAC (bacterial artificial chromosome) clones have previously identified TGFBR3 and MGEA5 as fusion partners. However, targeted RNA-sequencing allowed for the correct identification of FBXW4 and not MGEA5 as the fusion partner of TGFBR3 in a subcutaneous PHAT, a finding further confirmed by RT-PCR. FBXW4 and MGEA5 share a common cytogenetic location at 10q24.32, thereby suggesting that the use of less precise technology may have led to inaccurate gene identification. The study of additional cases is however required.

Hemosiderotic Fibrolipomatous Tumor on FDG PET/CT

A 74-year-old woman with a history of melanoma 10 years ago presented worsening swelling pain associated with a lump in her inner left thigh. Metastatic disease was suspected and for this reason, FDG PET/CT was performed. The images demonstrated peripherally increased FDG activity in the lump with a centrally photopenic region. Postsurgical pathological examination showed a hemosiderotic fibrolipomatous tumor.

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.

Establishment of a spontaneously transformed cell line (JU-PI) from a myxoinflammatory fibroblastic sarcoma

Myxoinflammatory fibroblastic sarcoma is a soft-tissue neoplasm most frequently found in the distal extremities of middle-aged adults. Most myxoinflammatory fibroblastic sarcoma are low-grade tumors with propensity for local recurrence after incomplete removal. We report a myxoinflammatory fibroblastic sarcoma which developed in the foot of a 41-year-old male and showed an exceptionally aggressive course with metastatic spread and fatal outcome within 16 months. We managed to establish a spontaneously transformed continuous cell line, called JU-PI, from a metastatic lesion. The JU-PI cells have a sub-tetraploid karyotype including the 1;10 chromosomal translocation and amplification of the proximal end of 3p; these features are considered genetic signatures of myxoinflammatory fibroblastic sarcoma. Both the primary tumor and the JU-PI cells showed nuclear expression of the TFE3 transcription factor but TFE3-activating chromosomal rearrangements were not found. To our knowledge, JU-PI is the first established myxoinflammatory fibroblastic sarcoma cell line. JU-PI cells offer a tool for investigating the molecular oncology of myxoinflammatory fibroblastic sarcoma.