Epithelioid hemangioendothelioma with extensive cystic change and CAMTA1 rearrangement

Epithelioid hemangioendothelioma (EHE) is a rare vascular neoplasm that has the ability to recur locally and metastasize. Thus, it is important to distinguish this tumor from other epithelioid vascular neoplasms. A 47‐year‐old man presented to our hospital with a pelvic mass with severe ischialgia and weight loss. Surgical resection was performed, and the mass was found to have dark red multiloculated cysts with hemorrhage and calcification. The histopathologic examination showed a central sclerotic, hypocellular zone and a peripheral cellular zone. Only the peripheral portion of the wall revealed nested tumor cells in light blue myxoid stroma. These tumors are typically composed of short strands or cords of bland epithelioid cells with occasional intracytoplasmic lumens embedded in a myxohyalinized stroma. The tumor cells were positive for CD31 and CD34 and negative for factor VIII‐related antigen, CK (AE1/AE3) and S‐100. The tumor nuclei showed distinct break‐apart signals with individual green and/or red signals, indicating the presence of CAMTA1 rearrangement. In this study, we report a case of EHE that was difficult to diagnose based on histology alone. Therefore, we also performed fluorescence in situ hybridization, and found that the tumor harbored a CAMTA1 gene rearrangement, which confirmed the diagnosis.     

TFE3‐rearranged hepatic epithelioid hemangioendothelioma—a case report with immunohistochemical and molecular study

A recurrent YAP1‐TFE3 gene fusion has been identified in WWTR1‐CAMTA1‐negative epithelioid hemangioendotheliomas arising in soft tissue, bone, and lung, but not in liver. We present the first case of TFE3‐rearranged hepatic epithelioid hemangioendothelioma in a 39‐year‐old Taiwanese woman. Computed tomography scan revealed multifocal, ill‐defined nodules involving both hepatic lobes. She then underwent deceased donor liver transplantation. Histologically, the tumors in the liver explant showed a biphasic growth pattern. One component was composed of dilated and well‐formed blood vessels lined by epithelioid cells with abundant eosinophilic cytoplasm, mimicking an alveolar pattern, whereas the other component was composed of cords and single cells, featuring intracytoplasmic vacuoles, separated by a myxoid stroma. The tumor cells showed vesicular nuclei and small indistinct nucleoli with mild to moderate cytologic atypia. Most tumor cells showed factor VIII, CD34, CD31, and TFE3 positivity in immunohistochemical study. Fluorescence in situ hybridization analysis for the tumor cells exhibited TFE3 gene rearrangement. The patient is currently alive, and no post‐operative tumor recurrence developed during a 13‐year follow‐up. Awareness of this rare vasoformative variant and identification of the gene rearrangement would be helpful on differential diagnosis with other high‐grade carcinoma and angiosarcoma of liver.     

ALK oncoproteins in atypical inflammatory myofibroblastic tumours: novel RRBP1‐ALK fusions in epithelioid inflammatory myofibroblastic sarcoma

ALK oncogenic activation mechanisms were characterized in four conventional spindle‐cell inflammatory myofibroblastic tumours (IMT) and five atypical IMT, each of which had ALK genomic perturbations. Constitutively activated ALK oncoproteins were purified by ALK immunoprecipitation and electrophoresis, and were characterized by mass spectrometry. The four conventional IMT had TPM3/4‐ALK fusions (two cases) or DCTN1‐ALK fusions (two cases), whereas two atypical spindle‐cell IMT had TFG‐ALK and TPM3‐ALK fusion in one case each, and three epithelioid inflammatory myofibroblastic sarcomas had RANBP2‐ALK fusions in two cases, and a novel RRBP1‐ALK fusion in one case. The epithelioid inflammatory myofibroblastic sarcoma with RRBP1‐ALK fusion had cytoplasmic ALK expression with perinuclear accentuation, different from the nuclear membranous ALK localization in epithelioid inflammatory myofibroblastic sarcomas with RANBP2‐ALK fusions. Evaluation of three additional uncharacterized epithelioid inflammatory myofibroblastic sarcomas with ALK cytoplasmic/perinuclear‐ accentuation expression demonstrated RRBP1‐ALK fusion in two cases. These studies show that atypical spindle‐cell IMT can utilize the same ALK fusion mechanisms described previously in conventional IMT, whereas in clinically aggressive epithelioid inflammatory myofibroblastic sarcoma we identify a novel recurrent ALK oncogenic mechanism, resulting from fusion with the RRBP1 gene. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Incidental in vivo detection of an epithelioid hemangioendothelioma of the mitral valve

Valvular epithelioid hemangioendotheliomas (EHE) are exceptional. To the authors' knowledge only four cases have been reported. Herein is described an EHE incidentally detected in the mitral valve of a 69-year-old woman with chronic rheumatic valvular heart disease. The 0.4 cm lesion was situated in the anterior leaflet and was discovered in the pathological study after mitral valve replacement. The patient was alive and well 6 months after operation. Review of the literature including the present report, revealed that the mean age was 60.2 years (range, 49-69 years). Symptomatic patients had clinical features of valvular disease or embolism. Each of the four cardiac valves can be affected. Mean tumor size was 2.4 cm (range, 0.4-8 cm). In 40% of cases the EHE was an incidental finding at autopsy or in a removed valve. In two cases the involved cusp was affected by chronic rheumatic disease. In conclusion, EHE is a rare lesion that can be an incidental finding and it should be considered in the differential diagnosis of valve tumors. Although EHE can present a histologically benign appearance, the correct pathological diagnosis is clinically important because the lesion can be potentially malignant. Regular follow up is suggested due to this potential.     

Pathological characteristics of liver biopsies in eight patients with hepatic epithelioid hemangioendothelioma

We aim to investigate the pathological characteristics of liver biopsies and their implications for the prognosis of hepatic epithelioid hemangioendothelioma (HEHE). Clinical data of eight patients (5 male, 3 female) with HEHE were analyzed retrospectively. Expression of CD34, FVIII, AE1/AE3, Hepa-par1, GPC3, CK19 and the proliferation index marker Ki-67 were determined by immunohistochemical staining. The clinical pathological features and effects of treatment on prognosis were investigated. Among the eight patients, four did not exhibit significant symptoms, while four showed symptoms such as abdominal distension, aversion to greasy food and mild fever. Two patients had single liver lesions, while multiple lesions were observed in six cases, in which the tumor cells exhibited spindle, irregular or epithelioid morphology, with scattered, streaked and nested distribution. Individual luminal cells were also visible, containing red cells and accompanied by mucoid or fibrous stroma. All cases were CD34 positive, one case was FVIII factor negative, two cases were AE1/AE3 positive, Ki-67 staining exceeded 15% in two cases, and nuclear fission was visible in two cases. Patients with nuclear fission and Ki-67 > 15% died within 2 years after artery embolization, liver transplantation without relapse was observed in two cases and one case survived with the tumor. The other patients without cellular atypia, without nuclear fission and with Ki-67 < 10% did not relapse during the 2-5 years of follow-up. HEHE can be diagnosed according to hematoxylin and eosin morphology and immunohistochemical characteristics in biopsies before treatment allowing the selection of different treatment protocols based on pathological characteristics.     

Minute perivascular epithelioid cell (PEC) nests in the abdominal lymph nodes—a putative precursor of PEComa

A perivascular epithelioid cell tumor (PEComa) is a peculiar growth defined as a mesenchymal tumor composed of histologically and immunohistochemically distinct perivascular epithelioid cells (PECs). Because neither normal counterparts nor precursor lesions of PEComa have been identified, we examined minute PEC nests, ranged from 0.8 mm to 10 mm, to investigate the possible origin of the PEComa. We examined a total of 80 677 para‐aortic and pelvic lymph nodes that were systematically dissected from 1656 patients for gynecological malignancies. The identified lesions were confirmed immunohistochemically with multiple PEC markers, including smooth muscle actin, HMB45, melan‐A, MiTF, ER and PgR. A total of 66 minute PEC nests were found in 21 patients (1.3% of the total population) with an average frequency of 3.1 lesions per patient. In cases of multiple involvement, 11 of 13 nests were located at the same level of multiple lymph node or on continuous levels. The lesions were preferentially distributed at the level of para‐aortic and high pelvic lymph nodes. All nests were positive for actin and HMB45, whereas the other markers were positive with varying frequencies. The minute PEC nests may be associated with the possible normal counterpart of PEComas.     

A rare case of BRAF V600E‐mutated epithelioid glioblastoma with a sarcomatous component

Epithelioid glioblastoma is a rare subtype of glioblastoma, but the coexistence of a sarcomatous component is even rarer. An 80‐year‐old woman was admitted to our hospital with somnolence. Magnetic resonance imaging revealed a cystic lesion with a solid component in the left temporal–parietal lobe. Histopathological examination of the resected tumor revealed three components; namely, typical glioblastoma, sarcomatous and epithelioid components at a ratio of about 5:3:2. All components were immunohistochemically positive for vimentin and mutated BRAF (V600E) and showed focal expression of glial fibrillary acidic protein and cytokeratin AE1/AE3, but they were negative for isocitrate dehydrogenase 1. Genetic analysis revealed that both the sarcomatous and epithelioid components harbored BRAF T1799A (V600E) mutation and homozygous deletion of cyclin‐dependent kinase inhibitor 2A/B. We diagnosed this tumor as epithelial glioblastoma with a sarcomatous component. Our results indicate that even when the epithelial component is not dominant, immunohistochemical and genetic investigation of BRAF mutations is useful for the diagnosis of glioblastoma subtypes. In particular, although the prognosis of epithelial glioblastoma is poor, potentially effective targeted therapies for BRAF V600E‐mutated tumors are available.     

Endothelin-1 gene and endothelin receptor A gene polymorphisms in severe pulmonary hypertension associated with rheumatic mitral valve disease

IntroductionEndothelin-1 (ET-1) gene polymorphisms are implicated in pathogenesis of idiopathic pulmonary arterial hypertension.MethodsWe studied ET-1 (Lys198Asn and 3A/4A) and endothelin receptor A (ET_A) gene (His323His) polymorphisms in 123 subjects with pulmonary hypertension associated with rheumatic mitral valve disease (PH-MVD) and 123 healthy controls.ResultsThe mutant homozygous Asn/Asn genotype in Lys198Asn and T/T genotype in His323His polymorphism was more prevalent in the PH-MVD group. Presence of Asn/Asn genotype was significantly associated with an increased risk (odds ratio 3.9).ConclusionsET-1 and ET_A gene polymorphisms are prevalent in the PH-MVD group suggesting that they may predispose to the development of PH.     

FN1–EGF gene fusions are recurrent in calcifying aponeurotic fibroma

Calcifying aponeurotic fibroma (CAF) is a soft tissue neoplasm with a predilection for the hands and feet in children and adolescents. Its molecular basis is unknown. We used chromosome banding analysis, fluorescence in situ hybridization (FISH), mRNA sequencing (RNA‐seq), RT‐PCR, and immunohistochemistry to characterize a series of CAFs. An insertion ins(2;4)(q35;q25q?) was identified in the index case. Fusion of the FN1 and EGF genes, mapping to the breakpoint regions on chromosomes 2 and 4, respectively, was detected by RNA‐seq and confirmed by RT‐PCR in the index case and two additional cases. FISH on five additional tumours identified FN1–EGF fusions in all cases. CAFs analysed by RT‐PCR showed that FN1 exon 23, 27 or 42 was fused to EGF exon 17 or 19. High‐level expression of the entire FN1 gene in CAF suggests that strong FN1 promoter activity drives inappropriate expression of the biologically active portion of EGF, which was detected immunohistochemically in 8/9 cases. The FN1–EGF fusion, which has not been observed in any other neoplasm, appears to be the main driver mutation in CAF. Although further functional studies are required to understand the exact pathogenesis of CAF, the composition of the chimera suggests an autocrine/paracrine mechanism of transformation. Copyright © 2015 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Low-grade fibromyxoid sarcoma: a clinicopathologic study of 18 cases, including histopathologic relationship with sclerosing epithelioid fibrosarcoma in a subset of cases

Low-grade fibromyxoid sarcoma (LGFMS) is an uncommon tumor with diverse histopathologic features. It has been found to be histopathologically and genetically related to hyalinizing spindle cell tumor with giant rosettes. Lately, sclerosing epithelioid fibrosarcoma (SEF) has been identified as another rare variant of fibrosarcoma. Very few studies have addressed the aspect of its histopathologic relationship with LGFMS. The present study was conducted to critically analyze the clinicopathologic features of a series of LGFMS cases, including identification of cases with histopathologic similarity with SEF. During a 7-year period, 18 LGFMS cases were diagnosed in 9 male and 9 female patients, had ages ranging from 10 to 69 years (median, 32.5 years), and were most commonly identified in the lower extremities (8 cases, or 44.4%). Most cases (16, 88.8%) showed “classic” features of LGFMS with mild (13 cases, or 72.2%) to moderate atypia (5 cases) and nil mitosis (12 cases, or 66.6 %). Variable features included whorling tumor growth pattern, small rosettes, perivascular hyalinization, and amianthoid-like collagen, along with epithelioid differentiation and nuclear pseudoinclusions within tumor cells. Four cases (22.2%) with large collagenous rosettes were diagnosed as hyalinizing spindle cell tumor with giant rosettes. Distinct SEF-like areas were observed in 6 cases (33.3%). On immunohistochemistry, consistent vimentin positively reinforced fibroblastic lineage of the tumor. Therapeutically, all 4 of 7 cases with available follow-up details, which underwent wide excisions, have been free of disease at 5 to 61 months. Eight excisions with unclear margins included 3 cases free of disease (24, 36, and 52 months) and 1 case with recurrence and metastasis. Two cases of marginal excision had tumor recurrences, including 1 case that recurred after 10 years. Low-grade fibromyxoid sarcoma is an uncommon sarcoma with diverse histopathologic features. Histopathologic relationship exists between LGFMS and SEF in a few cases. An LGFMS is optimally managed with surgical wide excision and follow-up.     

Undifferentiated round cell sarcomas with novel SS18‐POU5F1 fusions

Despite significant recent advances in characterizing the molecular pathogenesis of undifferentiated round cell neoplasms, rare cases remain unclassified. Here, we report two distinctive undifferentiated round cell tumors occurring in young adults. One tumor presented intrabdominally and the other arose within the abdominal wall. One patient died of disease following local and distance recurrence, despite aggressive chemotherapy and radiotherapy. Morphologically, both tumors were similarly composed of primitive round to epithelioid cells arranged in nests, sheets, and trabecular patterns. The cytoplasm was scant and amphophilic, while the nuclei were round and uniform with brisk mitotic activity. Focal necrosis was present. Immunohistochemically, both tumors were variably positive for S100 and EMA, and one case focally expressed cytokeratin and TLE1. Targeted RNA sequencing revealed in both an identical SS18‐POU5F1 fusion gene. Fluorescence in situ hybridization was performed which confirmed SS18 and POU5F1 gene rearrangements. Expression data, relative to over 200 other mesenchymal neoplasms that had undergone targeted RNA sequencing on the same platform, suggested the SS18‐POU5F1 tumors cluster with EWSR1/FUS‐POU5F1‐positive myoepithelial tumors. In view of our limited sample size, additional studies are needed to characterize the breadth of clinical and pathologic findings in these neoplasms. In addition, further investigation is necessary to determine whether this entity represents a clinically aggressive and phenotypically undifferentiated variant of myoepithelial tumors, or perhaps an altogether novel category of undifferentiated round cell sarcoma.     

Spectrum of cytopathologic features of epithelioid sarcoma in a series of 7 uncommon cases with immunohistochemical results,including loss of INI1/SMARCB1 in two test cases

Diagnosis of an epithelioid sarcoma (ES) is challenging on fine needle aspiration cytology (FNAC) smears. There are few documented series describing cytopathologic features and immunostaining results of ESs. The present study describes cytopathologic features of seven cases of ES. All seven tumors occurred in males within age‐range of 22–61 years; in sites, such as forearm (n = 3), hand (n = 2), thigh (n = 1), and inguinal region (n = 1). FNAC was performed for metastatic lesions (n = 5), recurrent lesions (n = 4), as well as for a primary diagnosis (n = 1). FNAC smears in most cases were moderate to hypercellular, composed of polygonal cells(seven cases) and spindle cells(three cases), arranged in loosely cohesive groups, non‐overlapping clusters, and scattered singly, containing moderate to abundant cytoplasm, defined cell borders, vesicular nuclei, and discernible nucleoli. Variable cytopathologic features identified in certain cases were “rhabdoid‐like” intracytoplasmic inclusions (n = 5), giant cells (n = 3), and interspersed scanty, metachromatic stroma (n = 4). Histopathologic examination revealed two cases of conventional‐type ES, three of proximal/large cell‐type ES, and two cases of mixed‐type ES, displaying features of conventional and proximal subtypes. By immunohistochemistry (IHC), tumor cells were positive for cytokeratin (CK)(4/5), epithelial membrane antigen (EMA) (6/6), panCK (1/1), vimentin (3/3), and CD34 (7/7). Tumor cells were completely negative for INI1/SMARCB1 (0/2) and CD31 (0/5). In our settings, FNAC was mostly performed in recurrent and/or metastatic cases of ES, and rarely for a primary diagnosis of ES. Important cytopathologic features of ESs include loosely cohesive, non‐overlapping clusters of polygonal cells with variable “rhabdoid‐like” and spindle cells. Optimal diagnostic IHC markers in such cases include CK, EMA, AE1AE3, CD34, and INI1/SMARCB1. Clinical correlation is imperative in all cases. Diagn. Cytopathol. 2016;44:636–642. © 2016 Wiley Periodicals, Inc.     

Novel and lethal case of cardiac involvement in DNM1L mitochondrial encephalopathy

Pathogenic DNM1L mutations cause a mitochondrial disorder with a highly variable clinical phenotype characterized by developmental delay, hypotonia, seizures, microcephaly, poor feeding, ocular abnormalities, and dysarthria. We report the case of an 8‐month‐old female with autosomal dominant, de novo DNM1L c. 1228G>A (p. E410K) mutation and mitochondrial disorder, septo‐optic dysplasia, hypotonia, developmental delay, elevated blood lactate, and severe mitochondrial cardiomyopathy leading to nonischemic congestive heart failure and cardiogenic shock resulting in death. This case suggests that cardiac involvement, previously undescribed, can be a clinically important feature of this syndrome and should be screened for at diagnosis.