Tumor fibroso calcificante intestinal: reporte de caso / Intestinal calcifying fibrous tumor: case report

El tumor fibroso calcificante (TFC) es una inusual lesión benigna de origen mesenquimal que puede presentar características similares a otros tumores más comunes. El caso involucra a una mujer de 36 años con un tumor en el yeyuno proximal, inicialmente sospechoso de ser un tumor del estroma gastrointestinal (GIST). Se realiza una resección quirúrgica, revelando un nódulo bien delimitado en el borde antimesentérico con características microscópicas típicas de TFC. Las células tumorales presentaban positividad para CD34 y negatividad para demás marcadores, diferenciándolo de otras neoplasias. El TFC puede confundirse con tumores más comunes debido a su apariencia, pero un diagnóstico preciso respaldado por inmunohistoquímica es esencial. La extirpación quirúrgica completa suele ser curativa. (AU)

Calcifying fibrous tumor (CFT) is a rare benign lesion of mesenchymal origin that may present similar characteristics to other more common tumors. We present the case of a 36-year-old woman with a tumor in the proximal jejunum, initially suspected to be a gastrointestinal stromal tumor (GIST). Surgical resection was performed, revealing a well-demarcated nodule at the anti-mesenteric border with microscopic features typical of a calcifying fibrous tumor. The tumor cells were positive for CD34 and negative for other markers, differentiating it from other neoplasms. Calcifying fibrous tumors can be confused with more common tumors because of its appearance, but an accurate diagnosis supported by immunohistochemistry is essential. Complete surgical excision is usually curative. (AU)

Cytological Perspective in a Case of Doege-Potter Syndrome With Hypoinsulinemic Hypoglycemia.

Solitary fibrous tumor (SFT) of the lung is a rare mesenchymal neoplasm of uncertain histogenesis, unknown molecular features, and unpredictable clinical behavior, characterized by NAB2-STAT6 fusion. Hypoglycemia accompanying SFT (Doege-Potter syndrome) is an uncommon presentation. We present the cytomorphological features on biopsy imprint smears of a histopathologically confirmed case of SFT of the lung with an uncommon presentation. A 76-year-old non-smoker, non-alcoholic, and non-diabetic man presented with complaints of intermittent episodes of confusion with syncopal attacks (>10 episodes) for six months. The patient had no respiratory complaints and no history of weight loss. Laboratory investigations revealed fasting blood sugar of 38 mg/dl with low serum insulin and C-peptide levels. Physical examination revealed reduced air entry on the left side of the chest. Chest X-ray showed left-sided homogenous opacity. High-resolution computed tomography (HRCT) of the chest showed a large left-sided lung mass. A biopsy was performed. Biopsy imprint smears were cellular and showed tumor cells arranged in clusters and fragments with traversing capillaries displaying monomorphic pump to oval nuclei, fine granular evenly dispersed chromatin, regular nuclear membrane, inconspicuous nucleoli, and a moderate amount of wispy cytoplasm. Foci of intercellular hyaline stromal material were noted. A cytodiagnosis of low-grade mesenchymal neoplasm was made. Histopathology revealed a cellular tumor comprising tightly packed round to fusiform cells arranged around blood vessels with intervening thick collagen, positive for CD99, vimentin, BCL2, CD34, and STAT6 and negative for EMA, CK AE1/AE3, S100, TLE1, and SMA. Familiarity with cytomorphology plays a pivotal role in clinching an early diagnosis of this rare neoplasm of the lung, particularly in the setting of presentation with hypoglycemia.

[Intestinal calcifying fibrous tumor: case report]. / Tumor fibroso calcificante intestinal: reporte de caso.

Calcifying fibrous tumor (CFT) is a rare benign lesion of mesenchymal origin that may present similar characteristics to other more common tumors. We present the case of a 36-year-old woman with a tumor in the proximal jejunum, initially suspected to be a gastrointestinal stromal tumor (GIST). Surgical resection was performed, revealing a well-demarcated nodule at the anti-mesenteric border with microscopic features typical of a calcifying fibrous tumor. The tumor cells were positive for CD34 and negative for other markers, differentiating it from other neoplasms. Calcifying fibrous tumors can be confused with more common tumors because of its appearance, but an accurate diagnosis supported by immunohistochemistry is essential. Complete surgical excision is usually curative.

Endobronchial solitary fibrous tumors: An enigma for diagnosis.

Solitary fibrous tumors (SFTs) are rare mesenchymal neoplasms constituting less than 2% of all soft tissue tumors. They typically originate in the thoracic cavity, mainly in the pleura, but can also occur in other various sites such as lung parenchyma, pericardium, and bronchus. In this study, a 49-year-old non-smoking female with a history of allergies presented to our pulmonary clinic with a chronic cough. An explorative bronchoscopy revealed an intrabronchial mass in the left superior bronchi, and a 68 Ga-DOTATOC positron emission computed tomography suggested a carcinoid tumor. Subsequent pulmonary segmentectomy unveiled a well-circumscribed polypoid lesion diagnosed as a low-grade bronchus SFT through histopathological and immunohistochemical assessments. The patient was asymptomatic after surgical excision and showed no other lesion during the 6-month follow-up. The endobronchial location of SFT is uncommon, with only a few reported cases in the literature, underscoring the necessity of considering various differential diagnoses, including carcinoid, mucoepidermoid carcinoma, endobronchial pleomorphic adenoma, hamartoma, leiomyoma, and metastasis, depending on location and imaging features. This report underscores the importance of careful histological and immunohistochemical evaluation in understanding and appropriately stratifying the risk associated with polypoid lesions.

Conjunctival leiomyosarcoma: A clinico-pathological study with in deep molecular characterization.

BACKGROUND: Primary and metastatic leiomyosarcomas (LMS) involving the orbital region are well known to occur however, the conjunctiva represents an extremely rare site of occurrence. METHODS: A 97-year-old male was referred to the Ocular Oncology Unit due to a rapidly growing painful mass (16×12×20 mm) in the nasal conjunctiva of his left eye. Wide excision followed by radiotherapy was performed. RESULTS: Based on the microscopic features (hypercellular neoplasm composed of spindle cells with cigar shaped and blunt ended nuclei with brightly eosinophilic fibrillary cytoplasm) and immunohistochemical findings (positive staining for Vimentin, Desmin, Caldesmon, and SMA and negative staining for AE1/AE3, EMA, CD117, S100, MelanA, SOX10, HMB45, TLE1, CD99, EMA and AE1 / AE3) the final diagnosis of grade 2 leyomiosarcoma was rendered. Moreover, 'in deep' DNA sequencing (>500 genes analysis) revealed a neoplasm with high TMB: 64 muts/Mb and numerous VUS and several pathogenic/oncogenic molecular alterations, including CNV loss or gain in > 10 genes. At the last follow-up visit, residual disease was observed in the superior fornix, at the nasal limbus and the cornea. At the time of writing, after a follow-up of 2 month the patients is still alive without evidence of metastatic disease. CONCLUSION: An uncommon molecular finding observed in our case was the presence of TSC1 gene mutation usually associated with soft tissue and gynecological PEComas. Our finding may harbor important therapeutic implications since the inactivation of the tumor suppressor genes TSC1 and TSC2 lead to upregulation of mTOR signaling, providing the rationale for target therapy with mTOR inhibitors. Additional studies on larger series are needed to validate our findings.

Superficial acral calcified chondroid mesenchymal neoplasm harboring an FN1::FGFR2 fusion and review of the literature.

Calcified chondroid mesenchymal neoplasm is a recently recognized bone and soft tissue entity primarily found in the extremities and the temporomandibular joint. This neoplasm is typically driven by the fusion of the FN1 gene with a kinase. In this case report, we provide a detailed account of a rare superficial calcified chondroid mesenchymal neoplasm located on the left big toe, characterized by an FN1::FGFR2 fusion. The tumor exhibited a peripheral collarette and consisted of large intradermal histiocytoid to epithelioid cells with no mitotic activity. These cells displayed fine chromatin and abundant pale eosinophilic cytoplasm, forming a swirling syncytium. They were interspersed with localized areas of glassy chondromyxoid matrix containing randomly mineralized calcific material and isolated osteoclast-like giant cells. RNA sequencing confirmed the presence of an FN1 (exon 29)::FGFR2 (exon 7) gene fusion. Our report emphasizes the importance for dermatopathologists to consider this entity when evaluating superficial lesions displaying mesenchymal, chondroid, and calcified attributes.

Calcified Chondroid Mesenchymal Neoplasms.

Calcified chondroid mesenchymal neoplasms (CCMN) represent a morphologic spectrum of related tumors. Historically, chondroid matrix or chondroblastoma-like features have been described in soft tissue chondroma, tenosynovial giant cell tumors (especially of the temporomandibular joint (TMJ) region), and in a subset of tophaceous pseudogout. Recently, these tumors have been found to share FN1-receptor tyrosine kinase (RTK) fusions. This review discusses the clinical, morphologic, immunohistochemical, and molecular genetic features of CCMN. The distinction from morphologic mimics is also discussed.

Expanding the spectrum of tyrosine kinase fusions in calcified chondroid mesenchymal neoplasms: Identification of a novel PDGFRA::USP8 gene fusion.

Calcified chondroid mesenchymal neoplasms represent a distinct, and recently recognized, spectrum of tumors. To date most cases have been reported to be characterized by FN1 gene fusions involving multiple potential tyrosine kinase partners. Following incidental identification of a tumor morphologically corresponding to calcified chondroid mesenchymal neoplasm, but with a PDGFRA::USP8 gene fusion, we undertook a retrospective review to identify and characterize additional such cases. A total of four tumors were identified. Each was multilobulated and composed of polygonal-epithelioid-stellate cells with a background of chondroid matrix containing distinctive patterns of calcification. Targeted RNA sequencing revealed an identical PDGFRA (exon 22)::USP8 (exon 5) gene fusion in each case. Subsequent immunohistochemical staining confirmed the presence of PDGFRα overexpression. In summary, we report a series of four tumors within the morphologic spectrum of calcified chondroid mesenchymal neoplasms. In contrast to prior reports, these tumors harbored a novel PDGFRA::USP8 gene fusion, rather than FN1 rearrangement. Our findings expand the molecular diversity of these neoplasms, and suggest they are united through activation of protein kinases.

Lip Granular Cell Tumor (GCT) in a Pediatric Patient: Critical Literature Review on Pediatric Intraoral GCT and Acquired and Congenital Intraoral Non-Neural GCT.

Granular cell tumor (GCT) is an uncommon benign neoplasm derived from Schwann cells, frequently affecting the oral cavity, skin, and gastrointestinal tract. On microscopy, pseudocarcinomatous squamous hyperplasia (PSH) and perineural involvement are potential diagnostic pitfalls. GCT should be differentiated from non-neural GCT (NN-GCT). A 13-year-old male patient was referred presenting a nodular lesion on the upper lip several months ago. After excisional biopsy, microscopy revealed GCT without PSH but presenting multifocal perineural involvement. By immunohistochemistry, ALK was negative, whereas Rb and INI1 expression was intact. Moreover, with few intraoral NN-GCTs being assessed, recent studies suggest that acquired dermal NN-GCT subgroup seems to correspond to ALK-rearranged variants of epithelioid fibrous histiocytoma. Accordingly, further research on this topic is strongly encouraged.

Gastrointestinal Stromal Tumor Masquerading As Acute Decompensated Heart Failure: A Challenging Diagnosis.

Gastrointestinal stromal tumors (GISTs) are rare lesions of the gastrointestinal tract that have a strong predisposition to the stomach and small intestine. We present a case of an 89-year-old female who initially presented to the emergency room with signs and symptoms of acute decompensated heart failure (HF) and was later discovered to have a 23-centimeter GIST in her abdominal cavity. This case emphasizes the implications of large intraperitoneal neoplasms and the unique constellation of symptoms they may present with.

Osteosarcoma in a free-living yellow armadillo (Euphractus sexcinctus).

An adult male free-living yellow armadillo (Euphractus sexcinctus) was found by hunters and referred for clinical evaluation because of a tumour-like lesion on the carapace. The animal was lethargic and weak with severe dehydration, enophthalmos and cachexia, and was euthanized because of its very poor clinical condition. Necropsy revealed a whitish, exophytic, irregular and moist mass (7 × 6.5 × 1.5 cm) in the caudal third of the carapace. On cut section, the mass was hard, compact, irregular and whitish. Histopathology revealed a densely cellular, expansive, poorly delimited neoplasm composed of malignant mesenchymal cells arranged in islands and cords, interspersed by numerous areas of irregularly mineralized osteoid matrix. Neoplastic cells were intensely immunolabelled for vimentin. The diagnosis of a high-grade osteosarcoma of osteoblastic subtype was based on the clinical, gross, histopathological and immunohistochemical findings. This first report of an osteosarcoma in an armadillo expands the list of armadillo diseases and will assist the management of these animals by veterinarians.

Diagnosis and surgical approach in treating glomus tumor distal phalanx left middle finger: A case report.

INTRODUCTION AND IMPORTANCE: Glomus tumors are rare mesenchymal neoplasms. These tumors originate from the glomus bodies and are commonly found in the fingertips, especially in the subungual location. The cause of this tumor is unknown. Clinically, the symptoms are non-specific and often not identified on physical examination and radiologically accompanied by rare cases, making it difficult to diagnose a glomus tumor. CASE PRESENTATION: Current report present a case of pain at the tip of the middle finger of the left hand in a woman for six years and worsening in the last two years. The patient has visited several doctors with analgesic therapy, but the complaints have not improved. A bluish nail was found on physical examination, and a clinical study with the Love's pin test and the Hildreth test had positive results. Radiographic examination showed destruction with cortical thinning of the medial aspect of the distal phalanx of the left middle finger, and MRI showed a lesion with an erosion of the distal middle finger. In this case, complete surgical excision and biopsy were performed using a transungual surgical approach. The sample was sent for microscopic examination, showing a glomus tumor. CLINICAL DISCUSSION: Cases with clinical symptoms of intense paroxysmal pain, exquisite point tenderness, and sensitivity to cold allow a clinical diagnosis in 90 % of cases. On clinical examinations such as Love's pin test, Hildreth's test, cold sensitivity test, and trans-illumination test with positive results and confirmed by MRI or ultrasound, the diagnosis of glomus tumor can be established. CONCLUSION: This case shows a glomus tumor in the distal phalanges of the middle finger of the left hand-diagnosis enforcement through detailed history taking and physical examination, confirmed by MRI and microscopic examination. Complete surgical excision is an effective treatment. In this case, using a transungual surgical approach based on preoperative MRI, the subungual lesion was found to provide the best exposure.

Rare forearm intramuscular myxoma: A case report.

Key Clinical Message: Intramuscular myxoma (IMM) is a benign soft tissue tumor of mesenchymal origin that occurs mainly in skeletal muscles which can be removed through surgery after diagnosis. Abstract: Intramuscular myxoma (IMM) is a benign soft tissue tumor of mesenchymal origin that typically occurs in skeletal muscles. Its diagnosis is based on magnetic resonance imaging (MRI) and histopathologic evaluation of the lesion. In our report, we describe the case of a 60-year-old female with an IMM in the supinator muscle of the right forearm, which was confirmed by MRI and histopathologic examination. Following surgery to remove the mass, a follow-up confirmed the patient's recovery and the absence of movement limitations in the elbow joint.

Mazabraud's syndrome: A case report supported by molecular studies and review of the literature.

Mazabraud's syndrome represents rare benign disorder characterized by simultaneous occurrence of fibrous dysplasia of bone and intramuscular myxomas within surrounding soft tissue. Mutations of GNAS1 gene were proven to be causative for this condition. Here, we present a case report of a patient with unusual manifestation of this disease, who developed a pathological fracture of the femur in the setting of monostotic fibrous dysplasia. The intramuscular myxoma of the thigh was discovered during the following orthopedic operation, where the intraoperative diagnosis became a pitfall of the case, as the intramuscular myxoma was initially diagnosed as a low-grade sarcoma from the frozen section. Apart from clinical findings, the diagnosis of Mazabraud's syndrome was further proven by histopathological evaluation and molecular studies of GNAS1 gene. This case raises awareness of such condition as it can easily become a diagnostic pitfall.

Tumor uterino que recuerda a los tumores de los cordones sexuales del ovario (UTROSCT): un caso clinicopatológico / Uterine tumour resembling ovarian sex cord tumours (UTROSCT): A clinicopathological case

Introducción: El tumor uterino que recuerda al tumor de los cordones sexuales del ovario (UTROSCT) es un tumor muy infrecuente de histogénesis incierta, incluido en la actual clasificación de tumores del estroma endometrial de la Organización Mundial de la Salud. Principales síntomas y/o hallazgos clínicos: Mujer de 48 años, sin antecedentes de interés, acudió a consulta por hipermenorreas en los últimos ciclos. La exploración ginecológica era normal. Diagnósticos principales, intervenciones terapéuticas y resultados: El estudio ecográfico mostró una lesión nodular submucosa de 26×21mm. Se le realizó histeroscopia diagnóstica, identificándose un mioma submucoso no accesible para extirpación ambulatoria. Se llevó a cabo histeroscopia quirúrgica procediéndose a miomectomía con asa de diatermia. Histológicamente se observó tejido muscular liso masivamente infiltrado por células de poco citoplasma con diferenciación glandular positivas con citoqueratinas, interpretándose como fragmentos de pared miometrial infiltrados por carcinoma. Se le realizó estudio de extensión e histerectomía. En la pieza quirúrgica no se identificó neoplasia residual. Se revaluó la biopsia previa y se amplió el estudio inmunohistoquímico, observándose positividad para marcadores de los cordones sexuales, epiteliales y musculares lisos. Ante estos hallazgos, el diagnóstico definitivo fue UTROSCT. Conclusión: El UTROSCT muestra generalmente un comportamiento benigno. Sin embargo, se considera de potencial maligno incierto, debido a que presenta una baja tasa de recurrencias y metástasis excepcionales. Desde el punto de vista histopatológico es importante reconocer esta entidad, ya que su histológica es variada imitando una amplia gama de tumores tanto benignos como malignos, por lo que es necesario realizar estudio inmunohistoquímico para su correcto diagnóstico.(AU)

Introduction: Uterine tumour resembling ovarian sex cord tumour (UTROSCT) is a very rare tumour of uncertain histogenesis, included in the current classification of endometrial stromal tumours of the World Health Organization. Main symptoms and/or clinical findings: 48-year-old woman with no history of interest, consulted for hypermenorrhoea in recent cycles. The gynaecological examination was normal. Main diagnoses, therapeutic interventions, and results: The ultrasound study showed a submucosal nodular lesion of 26×21mm. A diagnostic hysteroscopy was performed, identifying a submucosal myoma not accessible for outpatient removal. Surgical hysteroscopy was performed, proceeding to myomectomy with loop diathermy. Histologically, smooth muscle tissue was observed massively infiltrated by cells with scant cytoplasm and positive glandular differentiation for cytokeratins, interpreted as fragments of the myometrial wall infiltrated by carcinoma. An extension study and hysterectomy were performed. No residual neoplasia was identified in the surgical piece. A previous biopsy was re-evaluated and an immunohistochemical study was extended, showing positivity for sexual cord, epithelial, and smooth muscle markers. Given these findings, the definitive diagnosis was UTROSCT. Conclusion: UTROSCT generally shows benign behaviour. However, it is considered to be of uncertain malignant potential, due to its low rate of recurrence and rare metastases. From the histopathological point of view, it is important to recognize this entity, since its histology is varied, mimicking a wide range of tumours, both benign and malignant, making it necessary to perform an immunohistochemical study for its correct diagnosis.(AU)

ALK-rearranged Mesenchymal Neoplasms: A Report of 9 cases Further Expanding the Clinicopathologic Spectrum of Emerging Kinase Fusion Positive Group of Tumors.

Anaplastic lymphoma kinase (ALK) fusions are oncogenic drivers in diverse cancer types. Although well established in inflammatory myofibroblastic tumor (IMT) and epithelioid fibrous histiocytoma (EFH), ALK rearrangements also occur in the emerging family of kinase fusion-positive mesenchymal neoplasms. We investigated 9 ALK-rearranged mesenchymal neoplasms (exclusive of IMT and EFH) arising in 6 males and 3 females with a wide age range of 10 to 78 years old (median 42 years). Tumors involved superficial and deep soft tissue (6) and viscera (3). Three were myxoid or collagenous low-grade paucicellular tumors with haphazardly arranged spindled cells. Three were cellular tumors with spindled cells in intersecting short fascicles or solid sheets. Three cases consisted of uniform epithelioid cells arranged in nests or solid sheets, with prominent mitotic activity and necrosis. Band-like stromal hyalinization was present in 6 cases. All tumors expressed ALK; four were positive for S100 and five were positive for CD34, while all were negative for SOX10. By targeted RNA sequencing, the breakpoints involved ALK exon 20; the 5' partners included KLC1, EML4, DCTN1, PLEKHH2, TIMP3, HMBOX1, and FMR1. All but two patients presented with localized disease. One patient had distant lung metastases; another had diffuse pleural involvement. Of the six cases with treatment information, five were surgically excised [one also received neoadjuvant radiation therapy (RT)], and one received RT and an ALK inhibitor. Of the four patients with follow-up (median 5.5 months), one remained alive with stable disease and three were alive without disease. We expand the clinicopathologic spectrum of ALK-fused mesenchymal neoplasms, including a low-grade malignant peripheral nerve sheath tumor-like subset and another subset characterized by epithelioid and high-grade morphology.

Adrenal Solitary Fibrous Tumor: A Case Report.

Solitary fibrous tumor is a mesenchymal neoplasm that first appeared in the literature as a pleural lesion, but over the last decades, it has been reported in many extrathoracic sites. Primary solitary fibrous tumor in the adrenal gland is very uncommon. Its biological behavior is variable but mostly benign. We report here a case of an apparently healthy woman who, in the context of the study of limb paresthesias, was diagnosed with an adrenal incidentaloma. Laboratory tests were performed, and no hormone hyperfunction was detected. Subsequently, a right adrenalectomy was performed, and the pathological study confirmed a solitary fibrous tumor. To the best of our knowledge, this is the 19th case reported in the literature of a primary solitary fibrous tumor originating from the adrenal gland and, notably, the first documented instance in Spain.

Tumor condromixoide ectomesenquimal: uma revisão sistemática e análise molecular de um caso extralingual / Ectomesenchymal chondromyxoid tumor: a systematic review and molecular analysis of an extra-lingual case

O tumor condromixoide ectomesenquimal (TCE) é uma neoplasia benigna rara, que afeta principalmente a língua e que exibe alta frequência da fusão RREB1-MRTFB. Microscopicamente, o TCE se assemelha com outras lesões condromixoides, sendo o mioepitelioma um dos principais desafios de diferenciação. Seu diagnóstico requer além da análise microscópica, a imuno-histoquímica. Revisões narrativas sobre o TCE já realizadas não contemplam uma análise sistemática da literatura. A fusão RREB1- MRTFB apesar de frequente em língua, foi positiva em um caso intra-ósseo, não tendo sido ainda descrita nos tecidos moles orais extra lingual. Sendo assim, o objetivo desse estudo foi sistematizar os dados da literatura com ênfase na microscopia do TCE, e relatar um caso extra lingual investigando a fusão RREB1-MRTFB. Uma busca eletrônica em 5 bases foi realizada em dezembro de 2021. Um total de 44 artigos com 101 casos de TCE foram incluídos. Microscopicamente, o TCE mostrou-se não encapsulado (95,5%), porém circunscrito (89,2%), de aspecto lobular (70,6%), entremeado por septos fibrosos (98%), sendo uma proliferação sólida em lençol, ilhas ou cordões (98%), em um padrão reticular (98,3%), cujas células eram fusiformes (77,5%), redondas e ovoides (70,6%) ou poligonais (54,9%), com citoplasma eosinofílico (34,3%), imersas em uma matriz mixoide (97,0%), condroide (88,0%) ou mixocondroide (X%). Na imuno-histoquímica as células mostraram maior positividade para vimentina (100%), GFAP (88,9%), S-100 (85,7%), CD56 (76,9%) e CD57 (75%). A fusão RREB1-MRTFB ocorreu em n=20/23; 87,0%. O presente caso clínico relatado é de um nódulo em face lingual da mandíbula em jovem de 15 anos, cuja morfologia mostrava as características mais frequentemente identificadas na revisão sistemática. A análise molecular confirmou o diagnóstico de TCE. O estudo contribui para um detalhamento das características morfológicas diagnósticas do TCE, bem como expandiu o conhecimento molecular do tumor em um caso extra lingual de um indivíduo brasileiro.

The ectomesenchymal chondromyxoid tumor (ECMT) is a rare benign neoplasm that mainly affects the tongue and exhibits a high frequency of the RREB1-MRTFB fusion. Microscopically, ECMT resembles other chondromyxoid lesions, with myoepithelioma being one of the main differentiation challenges. Its diagnosis requires not only microscopic analysis but also immunohistochemistry. Narrative reviews on ECMT conducted so far do not encompass a systematic analysis of the literature. The RREB1-MRTFB fusion, despite being frequent in the tongue, has been tested positive in an intraosseous case, and it has not yet been described in extra-lingual oral soft tissues.Therefore, the aim of this study was to systematize the literature data with an emphasis on ECMT microscopy and report an extra-lingual case investigating the RREB1-MRTFB fusion. An electronic search across 5 databases was conducted in December 2021. A total of 44 articles comprising 101 cases of ECMT were included. Microscopically, ECMT was found to be non-encapsulated (95.5%), yet circumscribed (89.2%), exhibiting a lobular appearance (70.6%), interspersed with fibrous septa (98%), forming a solid proliferation in sheets, strands and cords (98%) in a reticular pattern (98.3%). The cells were spindle-shaped (77.5%), round and ovoid (70.6%), or polygonal (54.9%), with eosinophilic cytoplasm (34.3%), embedded in a myxoid matrix (97.0%), and chondroid (88.0%). Immunohistochemically, there was higher positivity for vimentin (100%), GFAP (88.9%), S-100 (85.7%), CD56 (76.9%), and CD57 (75%). The RREB1-MRTFB fusion occurred in n=20/23; 87,0%. The present clinical case reportes a nodule on the lingual aspect of the mandible in a 15-year-old individual, whose morphology exhibited the most frequently identified characteristics in the systematic review. The molecular analysis confirmed the diagnosis of ECMT. The present study not only contributes to a detailed understanding of the morphological diagnostic features of ECMT but also expands the molecular knowledge of the tumor based in an extra-lingual case of a Brazilian individual.

Recurrent meningeal malignant tumor: Assessment of differences in the solitary fibrous tumor/hemangiopericytoma spectrum through a case report / Tumor maligno recurrente de origen meníngeo: evaluación de las diferencias de la entidad tumor fibroso solitario/hemangiopericitoma mediante un caso clínico

Solitary fibrous tumors (SFTs) are neoplasms that grow from mesenchymal fusiform cells. In the central nervous system, meninges are the common origin of these neoplasms. Although literature reports mostly SFT as benign neoplasm, malignancy data have been described in recurrences or metastatic lesions. Definitive diagnosis includes immunohistochemical profiles assessing cellular positivity for CD34, vimentin, CD99 and Bcl-2. Recent studies have demonstrated NAB2-STAT6 gene fusion as a distinct molecular feature of SFT with overexpression of the fusion protein NAB2-STAT6 in nuclei of these cells. Since several years, pathologists have grouped SFT and hemangiopericytomas (HPC) as different phenotypes of the same entity although both neoplasms do not share numerous features. This article, based on a case of a recurrent malignant SFT, aims to emphasize differences in the SFT/HPC spectrum due to the diagnostic, therapeutic and prognostic implications (AU)

Los tumores fibrosos solitarios (TFS) son neoplasias que crecen a partir de células mesenquimales y las meninges constituyen su origen preferente en el sistema nervioso central. Aunque la literatura relaciona la mayoría de los TFS como neoplasias benignas, se describen datos de malignidad en recidivas tumorales o lesiones metastásicas. El diagnóstico definitivo incluye el perfil inmunohistoquímico, que evalúa la positividad celular para CD34, vimentina, CD99 y Bcl-2. Estudios recientes han demostrado la fusión del gen NAB2-STAT6 como una característica molecular distintiva de los TFS, con sobreexpresión de la proteína de fusión NAB2-STAT6 en los núcleos de las células. Los patólogos han agrupado los TFS y los hemangiopericitomas como diferentes fenotipos de una misma entidad, aunque ambas neoplasias no comparten numerosas características. Este artículo, basado en un caso de una lesión maligna recurrente, tiene como objetivo enfatizar las diferencias en el espectro SFT/hemangiopericitoma por sus implicaciones diagnósticas, terapéuticas y pronósticas (AU)