Unusual Mesenchymal Tumor Research Articles

Liposarcoma del cordón espermático

Introduction: liposarcoma of the spermatic cord (LSC) is a rare condition and accounts for about 3 to 7% of all paratesticular sarcomas. A case is presented in an 80-year-old patient who consulted for a left inguinoscrotal painless swelling, that had been present for several years. Physical examination revealed a soft left hemiscrotal tumor that appeared not to be adherent to the testicle. Ultrasonography showed a solid, heterogeneous hyperschoic paratesticular mass with central calcifications and peripheral hypervascularity. During surgery, a diffuse lipomatous tumor was found in the spermatic cord on the superior pole of the left testicle, separated from it. Anatomopathological examination revealed a well-differentiated liposarcoma of the spermatic cord. Discussion: this neoplasm features a slow-growing palpable paratesticular mass. This site of occurrence is rare and represents 7 to 10% of all scrotal tumors. Imaging differentiation between LSC and benign lesions is sometimes challenging. Surgical treatment should include radical orchiectomy wide local excision, and spermatic cord and inguinal ring surrounding soft tissue resection. Conclusion: spermatic cord liposarcoma is a rare and unusual mesenchymal tumor and should be considered among the differential diagnoses of scrotal tumors.

High-Grade Endometrial Stromal Sarcoma: Molecular Alterations and Potential Immunotherapeutic Strategies.

Endometrial stromal tumor (EST) is an uncommon and unusual mesenchymal tumor of the uterus characterized by multicolored histopathological, immunohistochemical, and molecular features. The morphology of ESTs is similar to normal endometrial stromal cells during the proliferative phase of the menstrual cycle. ESTs were first classified into benign and malignant based on the number of mitotic cells. However, recently WHO has divided ESTs into four categories: endometrial stromal nodules (ESN), undifferentiated uterine sarcoma (UUS), low-grade endometrial stromal sarcoma (LG-ESS), and high-grade endometrial stromal sarcoma (HG-ESS). HG-ESS is the most malignant of these categories, with poor clinical outcomes compared to other types. With advances in molecular biology, ESTs have been further classified with morphological identification. ESTs, including HG-ESS, is a relatively rare type of cancer, and the therapeutics are not being developed compared to other cancers. However, considering the tumor microenvironment of usual stromal cancers, the advance of immunotherapy shows auspicious outcomes reported in many different stromal tumors and non-identified uterine cancers. These studies show the high possibility of successful immunotherapy in HG-ESS patients in the future. In this review, we are discussing the background of ESTs and the BCOR and the development of HG-ESS by mutations of BCOR or other related genes. Among the gene mutations of HG-ESSs, BCOR shows the most common mutations in different ways. In current tumor therapies, immunotherapy is one of the most effective therapeutic approaches. In order to connect immunotherapy with HG-ESS, the understanding of tumor microenvironment (TME) is required. The TME of HG-ESS shows the mixture of tumor cells, vessels, immune cells and non-malignant stromal cells. Macrophages, neutrophils, dendritic cells and natural killer cells lose their expected functions, but rather show pro-tumoral functions by the matricellular proteins, extracellular matrix and other complicated environment in TME. In order to overcome the current therapeutic limitations of HG-ESS, immunotherapies should be considered in addition to the current surgical strategies. Checkpoint inhibitors, cytokine-based immunotherapies, immune cell therapies are good candidates to be considered as they show promising results in other stromal cancers and uterine cancers, while less studied because of the rarity of ESTs. Based on the advance of knowledge of immune therapies in HG-ESS, the new strategies can also be applied to the current therapies and also in other ESTs.

Metastatic malignant PEComa of the brain: An unusual entity with rare presentation

Perivascular epithelioid cell tumor (PEComa) is an unusual mesenchymal tumor comprised histological and immunohistochemically distinctive perivascular epithelioid cells exhibiting myomelanocytic phenotype. We hereby report the case of a 59-year-old female who presented with sudden headache, vomiting, and transient decreased vision with contrast MRI suggestive of the right occipital mass. Biopsy from the right occipital craniotomy mass was reported as metastatic malignant melanoma. The case was referred to our hospital for review. We considered a differential diagnosis of metastasis from malignant melanoma, poorly differentiated carcinoma, high-grade glioma, PEComa, hemangioblastoma, and high-grade sarcoma. A post-operative whole-body PET/CT scan revealed a metabolically active lesion in the endometrium that seems to be primary. It is suggested to consider PEComa as a differential diagnosis in poorly differentiated malignancy and to evaluate accordingly with appropriate immunohistochemistry markers. This is the third reported case of metastatic malignant PEComa to the brain as per the English literature.

Xanthogranulomatous epithelial tumor: report of 6 cases of a novel, potentially deceptive lesion with a predilection for young women

Epithelial marker expression and/or epithelial differentiation, as well as “anomalous” expression of keratins, are features of some soft tissue tumors. Recently, we have encountered an unusual mesenchymal tumor composed of bland, distinctly eosinophilic, keratin-positive epithelial cells, which were almost entirely obscured by xanthogranulomatous inflammation. Six cases were identified (5 F, 1 M; 16–62 years (median 21 years)) arising in soft tissue (n = 4) and bone (n = 2) and ranging in size from 2 to 7 cm. The tumors were generally circumscribed, with a fibrous capsule containing lymphoid aggregates, and consisted in large part of a sheet-like proliferation of foamy histiocytes, Touton-type and osteoclast-type giant cells, and chronic inflammatory cells. Closer inspection, however, disclosed a distinct population of uniform, cytologically bland mononuclear cells with brightly eosinophilic cytoplasm arranged singly and in small nests and cords. Overt squamous and/or glandular differentiation was absent. By immunohistochemistry, these cells were diffusely positive with the OSCAR and AE1/AE3 keratin antibodies, and focally positive for high-molecular weight keratins; endothelial and myoid markers were negative and SMARCB1 was retained. RNA-seq identified a PLEKHM1 variant of undetermined significance in one case, likely related to this patient's underlying osteopetrosis. Follow-up to date has been benign. In summary, we have identified a novel tumor of soft tissue and bone with a predilection for young females, provisionally termed “xanthogranulomatous epithelial tumor”. These unusual lesions do not appear to arise from adnexa, or represent known keratin-positive soft tissue tumors, and the origin of their constituent epithelial cells is obscure. The natural history of this distinctive lesion appears indolent, although study of additional cases and longer term follow-up are needed.

Liver pecoma: perivascular epithelioid tumor. a case report.

Background: Perivascular epithelioid cell tumors (PEComa) are an unusual mesenchymal tumors family, including the classic angiomyolipoma (AML), lypmphangioleiomyomatosis and clear-cell tumors, that can arise from different locations of the body [1–4]. We present a rare case of a Liver PEComa. Methods: A 58-year-old female with no background of cirrhosis or any other liver disease, who in an abdominal ultrasound, presented an exophytic heterogenic/solid mass of 5x6 cm in the left lateral section. Computed Tomography found a hypodense mass of 6.2x4.9x6.2 cm with fat density areas, quickly enhanced in the arterial phase and becoming less enhanced on venous and delayed phases of imaging, suggesting a PEComa as diagnosis. Laparoscopic Left Lateral Sectionectomy was performed. Pathology findings were a mix of three type of components: Adipose, vascular and perivascular epithelioid cells, HMB-45+, with conclusive findings of an angiomyolipoma. The patient was discharged at the second postoperative day, with no complications so far. Results: Liver PEComas were before considered as benign tumors, with surgical treatment in selected cases. The publications in the medical literature of some cases that confirm a malign transformation of AML have made the surgical indications for this pathology a controversial issue, recommending it in exophytic, >5cm or fast growing tumors [1–3]. Conclusion: Nowadays, liver PEComas are considerate as rare tumors with risk of malignancy in some cases, making the surgical intervention the primary treatment.

Aggressive angiomyxoma of the vulva: A case report

Aggressive angiomyxoma (AA) is an unusual mesenchymal tumor. AA occurs most commonly in women of reproductive age and is located in the perineal or pelvic region. This is a distinct soft tissue tumor that has a prominent myxoid matrix and numerous thin-walled blood vessels and may have an aggressive local recurrence. The tumors have the characteristics of large size (usually greater than 10 cm) and slow growth, and are not painful. The standard treatment for AA is total excision and close follow-up. We announce a case of a 35 year-old female presenting with a pedunculated AA on the right labium majora that has not relapsed for seven years.

Acquired reactive digital fibroma: A clinicopathologic report of 5 cases of a new entity

Fibroblastic proliferations in the dermis comprise a heterogeneous group of disorders that can pose diagnostic challenges. We sought to study the clinicopathologic features of this tumor. We reviewed the clinicopathologic features of 5 unusual mesenchymal tumors of the digits that, to our knowledge, correspond to an entity not previously described. The patients were 5 men. All cases were located in the digits and were associated with history of trauma. Histopathologically, the neoplasms were located mainly in the reticular dermis. The tumors consisted of solitary nodules composed of fascicles of benign-appearing spindle cells devoid of cytologic atypia. The spindle cells formed short fascicles arranged in a haphazard manner. On immunohistochemistry, the tumor cells expressed vimentin and in 2 cases, CD34. The tumor cells were negative for smooth muscle actin (SMA), desmin, h-caldesmon, epithelial membrane antigen (EMA), S100, CD68, CD99, and beta-catenin. Only 5 cases were studied. Awareness of this entity is of importance to avoid misdiagnosis with other conditions. Based on the immunohistochemical pattern, we believe that these tumors are fibroblastic in origin. The peculiar gross appearance and location of the lesions is clinically quite distinctive and may lead to confusion with other neoplastic and reactive processes.

Perivascular epithelioid cell tumor located retroperitoneally with pulmonary lymphangioleiomyomatosis: report of a case

Perivascular epithelioid cell neoplasms, also known as "PEComas", are unusual mesenchymal tumors, exhibiting perivascular epithelioid cell differentiation and characterized by a mixed myogenic and melanocytic phenotype. "PEComas not otherwise specified" (PEComas-NOS) are especially rare; consequently, there are no published large series, but only case reports. These tumors are rarely located retroperitoneally, with only about 15 such cases reported. We report a case of pulmonary diffuse lymphangioleiomyomatosis with large retroperitoneal PEComa-NOS in a 66-year-old woman. Treatment consisted only of tumor resection, without additional adjuvant therapy. We emphasize the importance of correct immunohistochemistry diagnosis, initiation of recommended treatment, and surveillance of this unique family of tumors.

Pleomorphic hyalinizing angiectatic tumor of the male breast: A heretofore unreported occurrence

Pleomorphic hyalinizing angiectatic tumor (PHAT) is considered an unusual mesenchymal tumor of intermediate malignant potential that is distinguished by a prominent angiectatic vasculature with clusters of thin-walled, fibrin-lined vessels surrounded by sheets of spindled and pleomorphic cells. This lesion occurs mostly in the subcutaneous soft tissues of the lower extremities. In this paper, the authors report the first case of PHAT involving the breast parenchyma of a 75-year-old man. The patient was referred to the hospital with a history of a painless left breast mass that had been growing for several years. The lesion did not recur after surgery. The tumor exhibited histopathologic and immunohistochemical features identical to those of a PHAT of other sites. The purpose of this report is to add a rare tumor to the differential diagnosis of mammary spindle cell neoplasms.

Malignant Solitary Fibrous Tumor of the Nasal Cavity

Solitary fibrous tumors (SFTs) are unusual mesenchymal tumors that were first described as primary spindle-cell neoplasms of the pleura. These tumors have been described in many other locations, including the urogenital system, orbit, mediastinum, and upper respiratory tract. Twenty-two cases of an SFT of the paranasal sinuses and nasal cavity have been reported, but none described a malignant SFT extending through the anterior skull base. A 70-year-old man had a 6-month history of unilateral left-sided epiphora and nasal obstruction. Computed tomography and magnetic resonance imaging showed a large left-sided nasal cavity mass with extension into the left extraconal orbit and intracranial extension through the left cribriform plate and ethmoid roof. The patient underwent preoperative embolization of the internal maxillary artery and a subsequent anterior craniofacial resection via a midfacial degloving approach and a left anterior craniotomy. Histopathological analysis of the specimen was consistent with a malignant SFT.

Pleomorphic hyalinizing angiectatic tumor of soft parts. A low-grade neoplasm resembling neurilemoma.

Fourteen examples of an unusual mesenchymal tumor characterized by sheets and fascicles of mitotically inactive, hemosiderin-stippled, spindled, and pleomorphic cells, situated around an angiectatic vasculature, are described. The 14 tumours developed in eight women and six men (aged 32-83 years) and ranged in size from 2.3 to 8 cm. Eleven cases presented in the subcutaneous tissues, of which eight were located in the lower extremity. All featured prominent clusters of thin-walled ectatic vessels surrounded by perivascular hyaline material representing a combination of fibrin and collagen. In three cases the perivascular hyalinization was so extensive that it constituted more than half of the total tumor area. The tumor cells were similar to those of malignant fibrous hystiocytoma but differed from them by the presence of prominent intranuclear cytoplasmic inclusions, the extreme scarcity of mitotic figures, and the occasional presence of CD-34 expression. These tumors also shared several features with neurilemomas, such as their unusual vasculature, intranuclear cytoplasmic inclusions, lack of mitotic figures, and abundance of mast cells. They could be distinguished from neurilemomas, however, by the usual presence of infiltrative margins and the absence of S-100 protein. Follow-up information on eight patients (6 months to 25 years) indicated recurrences in four cases, with one of the three patients experiencing numerous recurrences over a 25-year period. No patient has developed metastases, however. We suggest that this tumor is a low-grade sarcoma of uncertain lineage in which the vascular changes are, in part, reflective of its slow growth.