TGFBR3 and MGEA5 Rearrangements in Pleomorphic Hyalinizing Angiectatic Tumors and the Spectrum of Related Neoplasms

An unusual presentation of dermatofibrosarcoma protuberans: A case of fibrosarcomatous dermatofibrosarcoma protuberans with pleomorphic angiectatic tumor-like changes

Dermatofibrosarcoma protuberans (DFSP) is a locally aggressive superficial mesenchymal neoplasm characterized by monomorphic spindle-cell proliferation with a storiform pattern. It can demonstrate pigmentation, myxoid changes, myoid differentiation, plaque-like growth, and fibrosarcomatous features; its varied presentation often complicates diagnosis. We report an extremely rare case of fibrosarcomatous DFSP with features reminiscent of a pleomorphic hyalinizing angiectatic tumor (PHAT) in a 73-year-old male. The diagnosis was confirmed using a reverse transcription polymerase chain reaction. To the best of our knowledge, PHAT-like changes in DFPS have not been described so far. Therefore, this report provides a novel variant of DFSP and expands the differential diagnosis of DFSP and PHAT.

Superficial CD34-Positive Fibroblastic Tumor

Superficial CD34-positive fibroblastic tumor is a mesenchymal neoplasm of "intermediate malignancy" recently included in the fifth edition of the World Health Organization classification of soft tissue and bone tumors. In this review, we summarize the current knowledge on this rare entity with a special focus on its clinicopathological features, morphologic spectrum, and differential diagnosis. We also provide data regarding recent discoveries on its molecular profile and discuss its prognosis and management.

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 of the Larynx

Pleomorphic hyalinizing angiectatic tumor (PHAT) is a rare, benign soft tissue tumor with uncertain pathogenesis and lineage most commonly found in the lower and upper extremities. No reports exist of this tumor metastasizing, though local recurrence is common. To date, only approximately 100 cases have been reported. We present the case of a patient presenting with hoarseness and dyspnea found to have PHAT of the larynx, a location previously unreported in the literature and requiring unique management considerations.

Pleomorphic hyalinizing angiectatic tumor, a rare localization: A case report

INTRODUCTION AND IMPORTANCE

Pleomorphic hyalinizing angiectatic tumor (PHAT) is a very rare soft tissue tumor with locally aggressive behavior but without metastasizing capacity. The most described localization is in the lower extremities. However, other localizations, such as breast or renal hilium, have already been described. Global literature about this type of tumor is rare. Our objective is to review other rare localizations and the main histopathology findings.

CASE PRESENTATION

We report the case of a 70 year old woman who underwent local surgery to remove a soft tissue mass which had a posterior anatomo-pathological diagnosis of PHAT. Histopathology analyses showed tumor cells proliferation and cellular pleomorphism, associated with hemosiderin pigment deposition and papillary endothelial hyperplasia. Immunohistochemical analyses demonstrated positive expression for CD34 with negative expression of SOX-100 and S-100. Secondary surgery was performed to extend margin resection for the purpose of obtaining negative margins.

CLINICAL DISCUSSION

PHAT is a very rare tumor originates in subcutaneous tissues. Although there is no pathognomonic sign, it is frequently found at the microscope hyalinized vasculature, positivity for CD34 or negativity for SOX100 and S-100. Surgery with negative margins is the gold standard treatment. No metastasizing capacity was described for this type of tumor.

CONCLUSION

The aim of this clinical case report - and subsequent literature review - is to update the data about PHAT in order to demonstrate its cytopathological and immunohistochemical characteristics, its differential diagnosis with other soft tissue and malignant tumors and its gold standard treatment.

Effect of Dan-Lou tablets on coronary heart disease revealed by microarray analysis integrated with molecular mechanism studies

Dan-Lou tablets (DLT) effectively treat coronary heart disease (CHD). However, its pharmacological mechanism in CHD treatment requires further investigation. This study aimed to elucidate the underlying pharmacological mechanisms of DLT in the treatment of CHD through clinical trials, microarray research, bioinformatics analysis, and molecular mechanism research. In this study, DLT improved coagulation function, endothelial injury, and levels of lipids, metalloproteases, adhesion molecules, inflammatory mediators, and homocysteine. The results of molecular biology research demonstrated that DLT can increase the gene and protein expressions of meningioma expressed antigen 5 (MGEA5) and mouse doubleminute 2 (MDM2) and inhibited the gene and protein expressions of signal transcription and transcription activator 5 B (STAT5B), tropomyosin-1 (TPM1), and aromatic hydrocarbon receptor nuclear transpose (ARNT). The results indicate that DLT reduced the extent of vascular endothelial damage in CHD rats by reducing the expressions of STAT5B, TPM1, and MDM2; inhibiting the inflammatory reaction; and increasing the expressions of ARNT and MGEA5.

Persistent Green-Blue Plaque in a Healthy Woman

A woman in her 30s presents with a bruise on her hand with a blue-green plaque that appeared after a twisting injury to the affected hand. What is your diagnosis?

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.

Nanohydroxyapatite Stimulates PD-L1 Expression to Boost Melanoma Combination Immunotherapy

Although checkpoint-inhibitor immunotherapy held tremendous advances, improving immune response during treatment has always been an urgent clinical issue. With the help of mRNA microarray technology, it was found that short rod-like nanohydroxyapatite (nHA) promoted the upregulation of CD274 and PD-L1 related gene transcription, which was confirmed by the significantly enhanced PD-L1 expression level in B16, B16F10, and 4T1 cells in vitro. Hence, an injectable in situ responsive hydrogel reservoir embed with nHA and PD-1/PD-L1 inhibitor was engineered for a combination immunotherapy by peritumoral administration. The results confirmed that the combinational strategy effectively suppressed tumorigenesis and tumor growth, recovered the abnormal lactate dehydrogenase, aspartate transaminase, and alanine aminotransferase indicators, and significantly elongated the life span of a tumor-bearing mouse. The substantive progress mainly derived from nHA-induced T cell infiltration reinforcement in a tumor site and CD8⁺ T cell polarization in spleen, implying that nHA might function as an immunomodulator for melanoma immunotherapy.

RNA-sequencing of myxoinflammatory fibroblastic sarcomas reveals a novel SND1::BRAF fusion and 3 different molecular aberrations with the potential to upregulate the TEAD1 gene including SEC23IP::VGLL3 and TEAD1::MRTFB gene fusions

Myxoinflammatory fibroblastic sarcoma (MIFS) has been shown to harbor various recurrent molecular aberrations; most of which, however, seem to be present in only a minority of cases. In order to better characterize the molecular underpinnings of MIFS, fourteen cases were analyzed by targeted RNA-sequencing (RNA-seq), VGLL3 enumeration FISH probe, and BRAF break-apart and enumeration probes. Neither t(1;10)(p22;q24) nor BRAF gene amplifications were found. However, VGLL3 gene amplification was detected in 5 cases by FISH which corresponded with an increase in VGLL3 expression detected by RNA-seq. In 1 of these cases, RNA-seq additionally revealed a novel SND1::BRAF fusion. Two of the 9 cases lacking VGLL3 amplification harbored either a SEC23IP::VGLL3 or a TEAD1::MRTFB rearrangement by RNA-seq, both confirmed by RT-PCR and Sanger sequencing. The detected molecular aberrations have a potential to either activate the expression of genes regulated by the transcription factors of the TEAD family, which are involved in tumor initiation and progression, or switch on the MEK/ERK signaling cascade, which plays an important role in cell cycle progression. Our results broaden the molecular genetic spectrum of MIFS and point toward the importance of the VGLL3-TEAD interaction, as well as the deregulation of the MEK/ERK pathway in the pathogenesis of MIFS, and may represent a potential target for therapy of recurrent or advanced disease.

Superficial CD34-Positive Fibroblastic Tumor: A Clinicopathologic, Immunohistochemical, and Molecular Study of 59 Cases

Superficial CD34-positive fibroblastic tumor (SCD34FT) is a rare soft tissue neoplasm that shows overlapping features with PRDM10-rearranged soft tissue tumor (PRDM10-STT). This study characterizes the clinicopathologic, immunohistochemical, and molecular features of SCD34FT in a series of 59 cases. Fluorescence in situ hybridization to assess for PRDM10 rearrangement was performed in 12 tumors. Immunohistochemistry for CADM3 and WT1 was performed; CADM3 was also assessed in histologic mimics. Our cohort of 33 male and 26 female had a median age of 42 (range: 14 to 85) years. Tumors were most commonly located in the lower limb (73%), upper limb (8%), back (7%), and supraclavicular region (3%). The median tumor size was 3.0 cm (range: 1.0 to 9.0 cm). Clinical follow-up in 32 patients (median duration: 26 mo) revealed 2 local recurrences (6%). One patient developed regional lymph node metastases which were completely excised. Microscopically, SCD34FT comprised spindled and pleomorphic cells with glassy cytoplasm and occasional granular cell change. Fluorescence in situ hybridization confirmed PRDM10 rearrangement in 3/8 cases (38%). SCD34FT frequently expressed CADM3 (95%) and WT1 (75%). CADM3 was less diffusely positive in pleomorphic hyalinizing angiectatic tumor (40%), pleomorphic liposarcoma (20%), and undifferentiated pleomorphic sarcoma (10%). We corroborate that SCD34FT is indolent but may rarely metastasize to lymph nodes without adverse outcomes. CADM3 and WT1 may be useful in the distinction from histologic mimics. Since cases of SCD34FT with and without demonstrable PRDM10 rearrangement were clinicopathologically indistinguishable, our study further supports that SCD34FT and PRDM10-STT likely constitute a single entity.

Overlapping morphological, immunohistochemical and genetic features of superficial CD34-positive fibroblastic tumor and PRDM10-rearranged soft tissue tumor

Superficial CD34-positive fibroblastic tumor (SCD34FT) is a recently recognized soft tissue tumor that is considered to be of borderline malignancy. The pathogenesis of this tumor remains incompletely understood, but it has been suggested that SCD34FT overlaps with tumors showing fusions involving the PRDM10 gene. Previous analyses of PRDM10-rearranged tumors have demonstrated that they have a distinct gene expression profile, resulting in high expression of CADM3 (also known as SynCam3), which can be detected immunohistochemically. Here, we investigated a series (n = 43) of SCD34FT or PRDM10-rearranged tumors and potential mimics (n = 226) with regard to morphological, genetic, and immunohistochemical features. The results show that SCD34FT and PRDM10-rearranged tumor are morphologically indistinguishable; 41 of 43 tumors of both entities are CADM3-positive. Hence, we suggest that they constitute a single entity, preferably referred to as SCD34FT. Expression of CADM3 was only rarely seen in other soft tissue tumors, except in tumors with Schwann cell differentiation. Thus, IHC for CADM3, in combination with the characteristic morphological features, is a valuable adjunct in the diagnosis of SCD34FT.

Atypical Spindle Cell/Pleomorphic Lipomatous Tumor with Pleomorphic Hyalinizing Angiectatic Tumor-Like Growth Pattern: A Search for Diagnostic Clues

Atypical spindle cell/pleomorphic lipomatous tumor (ASPLT) is a newly described adipocytic tumor type, recently included as a separate tumor entity in the fifth edition of the World Health Organization (WHO) classification of soft tissue and bone tumors. Here, we describe a case of an ASPLT with a striking pleomorphic hyalinizing angiectatic tumor (PHAT)-like growth pattern and discuss the diagnostical clues, which led to the diagnosis of ASPLT. To our knowledge, a PHAT-like growth pattern has not yet been reported in the setting of ASPLT.

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.

Rapidly fatal SMARCA4-deficient undifferentiated sarcoma originating from hybrid hemosiderotic fibrolipomatous tumor/pleomorphic hyalinizing angiectatic tumor of the foot

Pleomorphic hyalinizing angiectatic tumor (PHAT) of soft parts and hemosiderotic fibrolipomatous tumor (HFLT) are two rare low-grade locally recurring neoplasms with predilection for the foot/ankle. Recent studies support a close link between the two entities, and origin of PHAT from HFLT and occurrence of hybrid HFLT/PHAT have been documented. Both lesions often harbor TGFBR3 or MGEA5 rearrangements. Rare sarcomas originating from HFLT/PHAT have been reported, typically resembling myxofibrosarcoma or myxoinflammatory fibroblastic sarcoma. We describe a novel SMARCA4-deficient undifferentiated sarcoma with rhabdoid features originating from hybrid HFLT/PHAT in the foot of a 54-year-old male. The tumor pursued a highly aggressive course with rapid regrowth after resection and multiple metastases resulting in patient's death within 5 months, despite systemic chemotherapy. Immunohistochemistry revealed SMARCA4 loss in the undifferentiated sarcoma, but not in the HFLT/PHAT. Molecular testing confirmed TGFBR3/MGEA5 rearrangements. This report expands the phenotypes of sarcomas developing from pre-existing PHAT/HFLT.

Superficial CD34-Positive Fibroblastic Tumor and PRDM10-rearranged Soft Tissue tumor are overlapping entities: a comprehensive study of 20 cases

INTRODUCTION

Superficial CD34-Positive Fibroblastic Tumor (SCD34FT) and PRDM10-rearranged soft tissue Tumor (PRDM10-STT) are rare mesenchymal tumors. These lesions have clinicopathological similarities, but their relationship remains controversial. This study aimed to characterize a series of cases of SCD34FT and PRDM10-STT.

METHODS AND RESULTS

ten lesions each of SCD34FT and PRDM10-STT were studied using immunohistochemistry, Array-Comparative genomic hybridization (aCGH), RNA-Sequencing and exome sequencing. Tumors mainly occurred in young adults, were generally small (<5 cm), and arose predominantly in the superficial soft tissues of the lower extremities. Follow-up data were available in 15 cases (SCD34FT, n= 7, median 16 months; PRDM10-STT, n= 8, median 14 months), local recurrences occurred in 4 cases (SCD34FT, 2/10; PRDM10-STT, 2/10) while no distant spread was documented. Morphologically, tumors were relatively well-circumscribed and composed of sheets and fascicles of spindle and pleomorphic cells showing low mitotic activity (<1/mm²) without necrosis. Other findings included: granular cell change, lipoblast-like cells, ectatic blood vessels with fibrinous material, myxoid stromal changes, metaplastic bone, and increased mitotic activity (>1/mm²). All tumors diffusely expressed CD34, while Pan-Keratin and Desmin were commonly seen focally. SynCAM3 was diffusely expressed in 12 cases (SCD34FT, n= 5; PRDM10-STT, n= 7), independently of fusion status. aCGH profiles were "flat" (PRDM10-STT, n=4; SCD34FT, n=2) and exome sequencing showed no recurrent pathogenic mutations (PRDM10-STT, n=2; SCD34FT, n=4). Overall, the only morphological features seen exclusively in PRDM10-STT were myxoid stromal changes (3/10) and metaplastic bone (2/10).

CONCLUSION

we expand the current knowledge on PRDM10-STT and SCD34FT and provide additional evidence for considering them as overlapping entities.

Cutaneous symplastic hemangioma: A series of four cases

Symplastic hemangiomas (SH) are benign vascular lesions that show atypia in vascular smooth muscle and interstitial cells with sparing of endothelial cells. We present four cases of this rare tumor. The patients (two males; two females) ranged in age from 57 to 83 years (median 74); lesions were located on the leg (n = 3) and back (n = 1), and ranged from 6 to 8 mm. SH were well-circumscribed and dermal-based, often with an epidermal collarette (3/4). They were characterized by the presence of variably atypical, hyperchromatic/pleomorphic epithelioid to spindled cells within vascular walls (3/4) and/or perivascular stroma (4/4). Atypical multinucleated cells were present in three of four cases. The overall mitotic rate was low (0-2 mitotic figures per 10 HPFs; mean 0.75 per 10 HPFs), but atypical mitotic figures were seen in two of four cases. Atypical cells were negative for SMA (0/2), desmin (0/2), AE1/3 (0/2), and CAM5.2 (0/1). ERG, CD31, and CD34 stains were positive in endothelial cells but negative in atypical cells (4/4). Lesional cells and vessels were negative for podoplanin (3/3). Symplastic hemangioma is a benign tumor with bizarre atypia that may be mistaken for malignancy. We present four cases of this rare entity to increase awareness of this tumor and discuss the differential diagnosis.

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.

Deep sequencing of myxoinflammatory fibroblastic sarcoma

Myxoinflammatory fibroblastic sarcoma (MIFS) has recurrent genetic features in the form of a translocation t(1;10)(p22-31;q24-25), BRAF gene fusions, and/or an amplicon in 3p11-12 including the VGLL3 gene. The breakpoints on chromosomes 1 and 10 in the t(1;10) cluster in or near the TGFBR3 and OGA genes, respectively. We here used a combination of deep sequencing of the genome (WGS), captured sequences (Cap-seq), and transcriptome (RNA-seq) and genomic arrays to investigate the molecular outcome of the t(1;10) and the VGLL3 amplicon, as well as to assess the spectrum of other recurrent genomic features in MIFS. Apart from a ROBO1-BRAF chimera in a t(1;10)-negative MIFS-like tumor, no fusion gene was found at RNA-seq. This was in line with WGS and Cap-seq results, revealing variable breakpoints in chromosomes 1 and 10 and genomic breakpoints that should not yield functional fusion transcripts. The most common genomic rearrangements were breakpoints in or around the OGA, NPM3, and FGF8 genes in chromosome band 10q24, and loss of 1p11-p21 and 10q26-qter (all simultaneously present in 6/7 MIFS); a breakpoint in or near TGFBR3 in chromosome 1 was found in four of these tumors. Amplification and overexpression of VGLL3 was a consistent feature in MIFS and MIFS-like tumors with amplicons in 3p11-12. The significant molecular genetic outcome of the recurrent t(1;10) could be loss of genetic material from 1p and 10q. Other recurrent genomic imbalances in MIFS, such as homozygous loss of CDKN2A and 3p- and 13q-deletions, are shared with other sarcomas, suggesting overlapping pathogenetic pathways.

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.

Superficial CD34 positive fibroblastic tumor: report of three cases and review of the literature

Superficial CD34 positive fibroblastic tumor (SCPFT) is a recently recognized, unique neoplasm with distinctive histomorphological features such as high pleomorphism, low mitotic rate, and diffuse CD34 reactivity. Hereby we present three cases of our experience with clinicopathological, morphological, and immunohistochemical characteristics. The patients were a 31-year-old female, 53-year-old female, and 33-year-old male. The tumors were all superficially located; left forearm, medial aspect of the left ankle, and left thigh, respectively. Histomorphologically they had expansile and focal infiltrative growth pattern consisting of highly pleomorphic spindle cells with intranuclear inclusions, yet low mitotic rate. Tumoral cells showed strong and diffuse reactivity for CD34. One of our cases showed focal and weak reactivity for pancytokeratin. Unlike the other two tumors, one case was positive for desmin. During the clinical follow-up, one case showed local recurrence four times. SCPFT is a newly recognized, borderline mesenchymal neoplasm of soft tissues that can show local recurrence or even rarely metastasize. To the best of our knowledge, this three case series is the first to be reported from Turkey. Our aim to report these three cases was to make contribution to the literature about this rare entity and increase awareness.

Cutaneous Spindle Cell Neoplasms: Pattern-Based Diagnostic Approach

Context.—

Spindle cell neoplasms arising in the skin comprise a heterogeneous group of tumors with divergent lineages. Cutaneous spindle cell neoplasms are relatively common and present surgical pathologists with diagnostic challenges. Recognition of their histopathologies is important for correct diagnosis and management. The current review presents a pattern-based diagnostic approach to common cutaneous spindle cell neoplasms that often cause diagnostic difficulties.

Objective.—

To provide a useful guide for diagnosis of cutaneous spindle cell neoplasms.

Data Sources.—

PubMed (US National Library of Medicine) reports and the authors' personal experiences are reviewed.

Conclusions.—

The authors briefly summarize the histologic features and differential diagnoses of common cutaneous spindle cell neoplasms.

Acral myxoinflammatory fibroblastic sarcoma with hybrid features of hemosiderotic fibrolipomatous tumor occurring 10 years after renal transplantation

Myxoinflammatory fibroblastic sarcoma is a rare malignant soft tissue neoplasm that typically arises on the distal extremities of adults. It usually behaves in a low-grade manner and its characteristic histology is of a lobulated proliferation of moderately atypical spindled to epithelioid cells, vacuolated cells, and enlarged or bizarre cells with prominent nucleoli, dispersed within myxoid stroma containing a mixed inflammatory cell infiltrate. The etiology of myxoinflammatory fibroblastic sarcoma remains unknown with no definite causal factors identified. We describe a case of myxoinflammatory fibroblastic sarcoma arising in the foot of a 77-year-old female, which rapidly recurred locally after initial excision and which arose 10 years after renal transplantation. The neoplasm also showed intermingled areas of hemosiderotic fibrolipomatous tumor. The patient also had multifocal areas of squamous cell carcinoma in situ of the foot and hand, in keeping with the clinical context of immune deficiency. This is the second case of myxoinflammatory fibroblastic sarcoma reported to occur after transplantation, but additionally shows hybrid features of hemosiderotic fibrolipomatous tumor, highlights immunocompromise/immunosuppressive therapy as a possible etiologic factor in their development, and adds to the growing number of myxoinflammatory fibroblastic sarcoma that has demonstrated aggressive behavior.

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.

Imaging and histological appearance of pleomorphic hyalinizing angiectatic tumors: A case series and literature review

Pleomorphic hyalinizing angiectatic tumors (PHATs) are rare mesenchymal soft tissue tumors of uncertain lineage and intermediate malignancy. The present study assesses two cases of PHAT and discusses the histological and immunophenotypical features, as well as the imaging appearance of these tumors on ultrasound, computed tomography (CT), magnetic resonance imaging and positron emission tomography/CT scans. The current study also reviews the literature and discusses the clinical management of these tumors. Wide local excision with tumor free margins is the current recommended treatment for PHAT. Surgical excision may be combined with low-dose radiation to reduce the risk of local recurrence. Patients should be followed up with serial imaging, as PHAT lesions tend to recur locally.

Treatment modalities and outcomes of pleomorphic hyalinizing angiectatic tumor: a systematic review of the literature

A systematic review of the cases documented in the literature regarding Pleomorphic hyalinizing angiectatic tumor of soft parts (PHAT) was performed in order to identify (1) location on presentation (2) surgical treatment modality (3) recurrence rate (4) any associations between location, age, histology, surgery type on recurrence. A systematic review of medical literature listed on PubMed was conducted identifying any prior case report and/or case series of diagnosed PHAT, with no exclusion based on language or time. Twenty-nine articles were identified removing any articles with duplicated cases yielding a total of 93 cases. Cases were broken down by gender, presenting location (UE/LE/axial), surgery type [wide local resection, non-wide local, wide local with radiation therapy (RT), non-wide local with RT], recurrence, and time to recurrence. The mean age at presentation was 54.5 ± 17.1 (range 10-89) with the 76% of cases appearing in the lower extremity (15% UE, 9% Axial). Of the 93 patients, 74 had a known surgical procedure, 31% WL, 40% NWL, 8% WL + RT, 1% NWL + RT. Of those treated surgically, 63 pts had documented follow-up and 18 (29%) had recurrence. A strong association was observed between surgery type and recurrence. Local recurrence was more common within the group undergoing NWLE in 52% (16/41) of cases (p = 0.002). Kaplan-Meier analysis showed an estimate mean time for recurrence of 43.87 months [95% confidence interval (CI) 24.52-63.22; and standard error (SE) 7.59] for the entire population. A trend was also seen toward males having a shorter disease-free survival than females (29.4 mos. vs. 69.5 mos.). No significant association seen between size, location, histology type and recurrence. PHAT has a characteristic presentation in the LE with a relatively high rate of local recurrence and slow-growing potential. Wide local excision appears to be superior in decreasing recurrence rates and a long-term follow-up period is needed.

Recurrent BRAF Gene Rearrangements in Myxoinflammatory Fibroblastic Sarcomas, but Not Hemosiderotic Fibrolipomatous Tumors

Myxoinflammatory fibroblastic sarcoma (MIFS) is a low grade soft tissue sarcoma with a predilection for acral sites, being associated with a high rate of local recurrence but very infrequent distant metastases. Although a t(1;10) translocation resulting in TGFBR3-MGEA5 fusion has been reported as a recurrent genetic event in MIFS, this abnormality is seen only in a subset of cases. As no studies to date have investigated the spectrum of alternative genetic alterations in TGFBR3-MGEA5 fusion negative MIFS, we undertook a genetic analysis of this particular cohort for further molecular classification. Triggered by an index case occurring in the finger of a 37-year-old female and harboring a novel TOM1L2-BRAF fusion by targeted RNA sequencing we investigated potential recurrent BRAF abnormalities by screening a large group of 19 TGFBR3-MGEA5 fusion negative MIFS by fluorescence in situ hybridization. There were 6 (32%) additional MIFS with BRAF genetic abnormalities, including 5 gene rearrangements and one showing BRAF amplification. Interestingly, VGLL3 amplification, a recurrent genetic abnormality coexisting with t(1;10) in some MIFS, was also detected by fluorescence in situ hybridization in 4/6 (67%) BRAF-rearranged MIFS, but not in the BRAF-amplified case. Up-regulated VGLL3 mRNA expression was also demonstrated in the index case by RNA sequencing. The 7 BRAF-rearranged/amplified MIFS arose in the fingers (n=3), and 1 each in wrist, forearm, foot, and knee, of adult patients (36 to 74 y; M:F=4:3). The histologic spectrum ranged from predominantly solid growth of plump histiocytoid to epithelioid tumor cells with focal myxoid change to a predominantly myxoid background with scattered tumor cells. Varying degree of inflammatory infiltrates and large tumor cells with virocyte-like macronucleoli were observed in most cases. Immunohistochemical stains of phosphorylated ERK, a downstream effector of BRAF activation, were positive in all 4 cases tested (2 diffuse strong, 2 focal strong). Unlike t(1;10), BRAF rearrangements were only found in MIFS but not in 6 hemosiderotic fibrolipomatous tumor (HFLT) lacking TGFBR3-MGEA5 fusions (including 2 pure HFLT, 2 hybrid HFLT-MIFS, and 2 associated with pleomorphic hyalinizing angiectatic tumors).

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

Hemosiderotic fibrolipomatous tumor is an unusual, distinctive soft tissue neoplasm with locally recurring potential, which most commonly occurs in the ankle and foot. Morphologic evidence strongly suggests that hemosiderotic fibrolipomatous tumor is related to another rare, locally aggressive tumor of the distal extremities, pleomorphic hyalinizing angiectatic tumor, with areas identical to hemosiderotic fibrolipomatous tumor seen at the periphery in most if not all pleomorphic hyalinizing angiectatic tumor. This morphologic evidence is further supported by molecular genetic data, showing recurrent TGFBR3 and/or MGEA5 rearrangements in both hemosiderotic fibrolipomatous tumor and pleomorphic hyalinizing angiectatic tumor. A possible link between hemosiderotic fibrolipomatous tumor and yet another low-grade sarcoma of the distal extremities, myxoinflammatory fibroblastic sarcoma, has also been suggested based on the occurrence of unusual examples of hemosiderotic fibrolipomatous tumor showing progression to myxoid sarcoma, demonstrating some but not all features of myxoinflammatory fibroblastic sarcoma. These "hybrid hemosiderotic fibrolipomatous tumor-myxoinflammatory fibroblastic sarcoma" also commonly show TGFBR3 and/or MGEA5 rearrangements. However, classic myxoinflammatory fibroblastic sarcoma lacks areas resembling hemosiderotic fibrolipomatous tumor, and shows a very low frequency of TGFBR3 and/or MGEA5 rearrangements in prospectively diagnosed cases. This suggests that so-called "hybrid hemosiderotic fibrolipomatous tumor-myxoinflammatory fibroblastic sarcoma" represents a form of malignant progression within hemosiderotic fibrolipomatous tumor, rather than a lesion strictly related to classic myxoinflammatory fibroblastic sarcoma. This article will review the morphologic features, genetic features, and differential diagnosis of these rare neoplasms, and discuss their interrelation, or lack thereof.

Soft Tissue Tumors of Uncertain Histogenesis: A Review for Dermatopathologists

The mesenchymal tumors discussed herein represent a heterogeneous group of neoplasms with distinctive morphologic, immunophenotypic, and molecular genetic features. These uncommon tumors often arise in the dermis and subcutis and can pose a major diagnostic challenge to dermatopathologists because they closely mimic melanoma, carcinoma, fibrous histiocytoma, schwannoma, or granulomatous inflammation. This article reviews the clinical presentation, histopathology, differential diagnosis, and diagnostic pitfalls of epithelioid sarcoma, clear cell sarcoma, perivascular epithelioid cell tumor, ossifying fibromyxoid tumor, pleomorphic hyalinizing angiectatic tumor, and hemosiderotic fibrolipomatous tumor. Associated molecular genetic findings are also briefly reviewed with an emphasis on their diagnostic usefulness.

Synovial Sarcoma Mimicking Pleomorphic Hyalinizing Angiectatic Tumor of Soft Parts: A Case Report

Synovial sarcoma is a high-grade sarcoma commonly affecting young adults. The sites of involvement include soft tissue near joints, lung, pleura, mediastinum, larynx, kidney, and buttocks. Histologic types include monophasic, biphasic, and undifferentiated. We report a unique case of synovial sarcoma with low-grade histologic features mimicking pleomorphic hyalinizing angiectatic tumor (PHAT) with indolent behavior for a period of 10 years. The tumor showed angiectatic blood vessels with fibrinous cuffing, hypocellular and hypercellular spindle cell areas with rare mitoses, and focal atypia in a myxoid background. TLE1 was positive with SYT gene translocation detected on fluorescent in situ hybridization. Cases of myxoinflammatory fibroblastic sarcoma and myxofibrosarcoma have been reported as exhibiting histologic features of PHAT. However, to the best of our knowledge, cases of synovial sarcoma mimicking PHAT have not been reported.

Sarcomatous transformation of a hemosiderotic fibrohistiocytic lipomatous tumor: a case report

Hemosiderotic fibrohistiocytic lipomatous tumors are rare neoplasms that were first described in 2000. Initially considered a benign lipotamous lesion of the soft tissues, nowadays they are considered to be a locally aggressive tumor. They occur mainly in the foot and ankle of women in their fifth and sixth decades, although they may be found in any place in the lower limbs and, more rarely, in other parts of the body. Histologically, hemosiderotic fibrohistiocytic lipomatous tumors consist of a mixture of mature adipose tissue, fusiform cell fascicles, macrophages that often contain cytoplasmic hemosiderin, mononuclear inflammatory infiltrate, and stroma that may be focally myxoid. Local recurrence is observed in nearly one-third of all cases. There is no consensus in the literature whether this tumor is a part of a spectrum that comprises pleomorphic hyalinizing angiectatic tumors and myxoinflammatory fibroblastic malignant tumors, or if it is an independent entity.

The authors report a case of a neoplasia after a diagnosis of a hemosiderotic fibrohistiocytic lipomatous tumor in a 38-year-old woman, with two recurrences and later sarcomatous transformation. An immunohistochemical study indicated myofibroblastic differentiation of a malignant neoplasm. To the best of the authors’ knowledge, there are only few reported cases of malignant transformation in hemosiderotic fibrohistiocytic lipomatous tumors.

Advances in the Genetic Characterization of Cutaneous Mesenchymal Neoplasms: Implications for Tumor Classification and Novel Diagnostic Markers

Cutaneous mesenchymal neoplasms often pose significant diagnostic challenges; many such entities are rare or show clinical and histologic overlap with both other mesenchymal and non-mesenchymal lesions. Recent advances in the genetic classification of many cutaneous mesenchymal neoplasms have not only helped define unique pathologic entities and increase our understanding of their biology, but have also provided new diagnostic markers. This review details these recent discoveries, with a focus on their implications for tumor classification and diagnosis.

Superficial CD34-positive fibroblastic tumour: a clinicopathological and immunohistochemical study of an additional series

AIMS

To describe an additional series of superficial CD34-positive fibroblastic tumour, a newly described neoplasm, in order to enhance the recognition of an emerging novel entity.

METHODS AND RESULTS

The clinicopathological features and immunophenotypes of 11 cases of superficial CD34-positive fibroblastic tumour were studied. There were eight males and three females, with a median age of 36 years. Tumours occurred in the thigh (n = 4), buttock (n = 3), shoulder (n = 2), upper arm (n = 1), and waist (n = 1). Histologically, all tumours were characterized by relative circumscription, pleomorphic spindled to polygonal cells with variably enlarged bizarre-appearing cells, intranuclear cytoplasmic pseudoinclusions, and extremely low mitotic activity. Immunohistochemically, neoplastic cells showed diffuse and strong expression of CD34 and focal staining of cytokeratin. Follow-up thus far has revealed an indolent clinical behaviour.

CONCLUSIONS

Superficial CD34-positive fibroblastic tumour represents a new member of the family of cutaneous CD34-positive spindle-cell tumours. Familiarity with its clinicopathological characteristics is helpful in avoiding confusion with a variety of cutaneous mesenchymal tumours with overlapping features.

Clinical implications of a rare renal entity: Pleomorphic Hyalinizing Angiectatic Tumor (PHAT)

Pleomorphic Hyalinizing Angiectatic Tumor (PHAT) is a rare benign lesion characterized by slow growth, infiltrative behavior and high rate of local recurrences. Only one case has been described in retroperitoneum, at renal hilum, but not involving pelvis or parenchyma. Here we present the first case of PHAT arising in the renal parenchyma. A nodular lesion in right kidney lower pole was diagnosed to a 61 year old woman. The patient underwent right nephrectomy. Microscopically, the lesion showed solid and pseudo-cystic components with hemorrhagic areas characterized by aggregates of ectatic blood vessels. Pleomorphic cells were characterized by large eosinophilic cytoplasm with irregular and hyperchromatic nuclei. Immunohistochemistry was performed and the lesion was classified as a Pleomorphic Hyalinizing Angiectatic Tumor (PHAT). Due to the clinical behavior of this tumor, in spite of its benign nature, review of the surgical margins and close follow up after partial nephrectomy are mandatory.

Advances in the clinicopathological and molecular classification of cutaneous mesenchymal neoplasms

In recent years, there have been several important refinements in the classification of cutaneous mesenchymal neoplasms, including the description of new tumour types, along with the identification of novel and recurrent molecular genetic findings. In addition to providing new insights into tumour biology, many of these advances have had significant clinical consequences with regard to diagnostics, management, and prognostication. Newly described entities include pseudomyogenic haemangioendothelioma, haemosiderotic fibrolipomatous tumour, and fibroblastic connective tissue naevus, which are reviewed in the context of the principal differential diagnoses and significant clinical implications. Genetic characterization of several soft tissue tumour types that occur in the skin has resulted in the identification of diagnostically useful markers: ALK gene rearrangement with corresponding ALK protein expression by immunohistochemistry in epithelioid fibrous histiocytoma; the WWTR1-CAMTA1 fusion gene with CAMTA1 protein expression in epithelioid haemangioendothelioma; MYC amplification and overexpression in radiation-associated angiosarcoma; and EWSR1 gene rearrangement in cutaneous myoepithelial tumours. Finally, the classification of intradermal smooth muscle tumours and unclassified/pleomorphic dermal sarcoma has been refined, resulting in both improved classification and improved prognostication. Many of the tumour types listed above are encountered not only by specialist dermatopathologists, but also by practising general surgical pathologists, and this review should therefore provide a widely applicable update on the histological and molecular classification of cutaneous mesenchymal neoplasms, along with the appropriate use of ancillary diagnostic tests, in particular immunohistochemistry, in the evaluation of such lesions and their histological mimics.

Cytologic and Histologic Features of Pleomorphic Undifferentiated Sarcoma Arising in a Hybrid Hemosiderotic Fibrolipomatous Tumor and Pleomorphic Hyalinizing Angiectatic Tumor: Report of an Unusual Case with a Literature Review

BACKGROUND

Pleomorphic hyalinizing angiectatic tumor (PHAT) and hemosiderotic fibrolipomatous tumor (HFLT) are low-grade neoplasms that share clinicopathologic features and recurring translocation t(1;10)(p22;q24) involving the TGFBR3 and MGEA5 genes. Coexistence of these tumors with a high-grade sarcoma is exceedingly rare and the cytologic features have not been widely described in the literature.

CASE

A 55-year-old female presented with a soft tissue tumor on the dorsum of the foot. Cytologic smears and corresponding core biopsies were composed of a population of markedly pleomorphic spindle cells seen singly and in loose clusters within a myxofibrous matrix and infiltrating fat, with coarse chromatin, prominent nucleoli, irregular nuclear contours and delicate to vacuolated cytoplasm. Intracytoplasmic hemosiderin granules and rare intranuclear cytoplasmic pseudoinclusions were identified. The histologic features of the excisional biopsy mirrored those of the cytologic preparations, but also demonstrated cellular foci of higher-grade sarcoma composed of markedly pleomorphic tumor cells with large vesicular nuclei and prominent nucleoli, exhibiting a mitotic index of 12 mitotic figures per 10 high-powered fields.

CONCLUSION

While HFLT/PHAT generally can be managed by wide local excision, it is important to be aware of their capacity to harbor higher-grade lesions with metastatic potential which may require more radical surgical excision.