Renal myxoma: A report of two cases and review of the literature
Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, New York 10021.American Journal of Surgical Pathology (Impact Factor: 5.15). 03/1994; 18(2):187-94.
Renal myxomas are rare neoplasms. Seven cases have been reported, of which only two are convincingly diagnosed as myxoma; the remaining cases exhibit features of sarcoma, fibroepithelial polyp, or myxolipoma. We report two additional cases; one in a 52-year-old man and another in a 68-year-old woman. They were discovered incidentally by radiological examination. The resected kidney in both patients contained a well-demarcated gelatinous intraparenchymal tumor, which consisted of occasional slender spindle cells scattered in an abundant myxoid stroma, closely resembling myxomas of other sites. The tumor cells showed immunoreactivity for vimentin but not for S-100 protein, epithelial membrane antigen (EMA), CAM 5.2, HHF-35, or smooth muscle actin. Ultrastructural features were of fibroblast-like cells with an elaborate network of cytoplasmic processes. The differential diagnosis of myxoid tumors of the kidney includes myxoid variants of renal sarcomas and carcinomas, renomedullary interstitial cell tumors, and fibroepithelial polyps. It is important to recognize the existence of a renal myxoma, to avoid confusing this benign tumor with the malignant neoplasms with secondary myxoid features that may involve the kidney.
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ABSTRACT: Myxomas are relatively rare tumors and most of them occur in the heart, skin, and soft tissues and bones. Renal myxomas are extremely rare neoplasms and very few cases have been reported in the literature. A review of medical literatures reveals no previous description of renal myxoma complicated with extensive areas of hemorrhage. So, we report such a case in a 43-year-old female. She had a left renal mass incidentally discovered during ultrasonography at a regular health checkup, and further computed tomography scan showed 4.9 × 3.1 cm mass with circular septal enhancement and ill-defined margin with the left psoas major muscle. Radical nephrectomy was performed because of suspected malignant renal tumor. Postoperative histopathology of resected specimen revealed the typical appearance of a myxoma associated with extensive hemorrhage.
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ABSTRACT: Myxoid lesions can be subdivided into (1) mainstream myxomas of soft tissues, (2) mainstream myxomas located outside the soft tissue, (3) inadequately substantiated myxomas, (4) myxoid soft tissue tumors or lesions not regarded as myxomas, (5) myxoid fatty conditions, (6) other soft tissue lesions and tumors that are sometimes markedly myxoid, (7) other soft tissue tumors in which myxoid foci may be seen, and (8) nonneoplastic myxoid conditions of soft tissue. More than 60 such conditions are listed and the five entities regarded as mainstream soft tissue myxomas (namely, intramuscular myxoma, juxta-articular myxoma, superficial angiomyxoma, aggressive angiomyxoma, and myxoid neurothekeoma [myxoma of nerve sheath]) are reviewed in detail. Intramuscular myxoma is exclusively intramuscular, usually affects middle-aged women, is most commonly located in the thigh, and does not recur after simple excision. Multiple intramuscular myxomas are rare and are usually associated with monostotic or polyostotic fibrous dysplasia and Albright's syndrome. Juxta-articular myxoma histologically resembles an intramuscular myxoma, but involves periarticular tendons, ligaments, joint capsules, muscles, and even the subcutis of adults. It may be associated with osteoarthritis of the adjacent joint. Some 30% recur locally. Superficial angiomyxoma also has been called cutaneous myxoma. It affects all ages, with a peak incidence in the third and fourth decades; arises in the trunk, lower limb, head, and neck regions; and usually measures less than 5 cm in diameter. Epithelial components are present in approximately 25% of tumors. Approximately one third recur locally, but there have been no metastases. Patients with multiple lesions may have the Carney complex. Aggressive angiomyxoma usually arises in the pelvic and perineal regions and affects females seven times as often as males. Tumors usually measure 10 cm or more in diameter, invade surrounding tissues, and recur in approximately 50% of cases. None have metastasized. Myxoma of nerve sheath (the myxoid variant of neurothekeoma) preferentially affects the dermis and subcutis of the cervicofacial areas and shoulders of young women. Most patients are younger than 40 years; one third of them are in the second decade of life. The majority of tumors measure between 0.5 and 1.5 cm. Only three of 102 cases compiled from the two largest published series recurred; none metastasized. The different clinicopathologic features and behavior of these five mainstream myxomas indicate that myxoma is not a single entity.
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ABSTRACT: Renal schwannomas are extraordinarily rare neoplasms; only six have been reported, the majority of which occurred in the renal pelvis. We report the clinical and pathologic features of four additional cases. The resected kidney in all patients contained a well-demarcated, yellow-tan, smooth, and bulging intraparenchymal tumor (mean size, 9.7 cm; range, 4 to 16 cm). Microscopically, three cases were classified as cellular schwannomas, and one was a usual-type schwannoma, with degenerative nuclear atypia. By immunohistochemistry, all tumors were strongly S-100 protein positive and negative for pan-cytokeratin, CD57, smooth muscle actin, desmin, and CD34. Epithelial elements were not noted in the tumors, and there was no history of any clinical syndromes in these patients. Analysis of the four cases showed the mean age at presentation to be 47 years (range, 18 to 84 years), with no sex predisposition (two men, two women). Most patients were asymptomatic, and all received a diagnosis of renal cell carcinoma and treated as having such. Recognition and awareness of these rare, benign tumors will assist in the differential diagnosis of spindle cell tumors of the kidney and prevent their misdiagnosis as sarcomatoid carcinomas of the kidney or renal sarcomas. Our study, the largest series to date of renal schwannomas, demonstrates a predilection for the cellular variant in the kidney, documents that these tumors may present in the nonhilar region of the kidney, and provides clinical evidence of their benign biologic behavior.
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