Retroperitoneal lesions represent a broad, diverse collection of entities; when they contain fat, the differential diagnosis, which ranges from benign to fully malignant lesions, substantially narrows. Lipomas rarely occur in the retroperitoneum; thus, fat-containing lesions in this location should never be dismissed as lipoma. Pelvic lipomatosis is the overgrowth of histologically normal fat in the extraabdominal compartments of the pelvis along the perirectal and perivesicular spaces. Infants and young children develop lipoblastomas rather than liposarcomas, which occur in older patients. Liposarcomas typically occur in patients 50-70 years old and manifest in multiple subtypes, with the most common being well-differentiated liposarcoma. Liposarcomas are histologically and radiologically protean, with no one imaging feature specific across the spectrum of subtypes. Hibernoma is a rare benign soft-tissue tumor composed of brown fat. Because hibernomas contain varied portions of brown and white fat as well as lesser amounts of myxoid material and spindle cells, their imaging features vary considerably. Teratomas are neoplasms that originate in pluripotent cells--benign or malignant germ cells--that give rise to a wide spectrum of mature or immature tissues that are foreign to the location in which they arise and which demonstrate varying amounts of organ formation. Myelolipoma, a benign tumor composed of mature fat and interspersed hematopoietic elements that resemble bone marrow, typically originate in an otherwise normal adrenal gland. Angiomyolipoma is composed of varying admixtures of blood vessels, smooth muscle cells, and adipose tissue; any one or two of these elements may predominate. Although these fat-containing lesions have overlapping radiologic features, use of demographic and clinical data helps refine the diagnostic options and treatment.
This report deals with 11 examples of renal angiomyolipomas (AML) which appear to include an epithelial element as a part of the neoplasm in the form of gross or microscopic cysts-usually both. There were seven females and four males between the ages of 20 and 70 years with mean age of 45 years. Three of these were known to be symptomatic: intermittent flank pain and gross hematuria for 2 months; recurrent hematuria both before and after flank trauma and a third patient with acute abdomen due to a ruptured tumor blood vessel. Cysts were described in three of the six cases where radiographic data were available. Seven tumors were in the right kidney and four in the left. In gross descriptions, cysts were mentioned in seven and they ranged from 6.0 to 2.0 cm with a median and mean maximal diameter of 5.0 and 4.0 cm, respectively. Microscopically, virtually all of the tumors included multiple smaller cysts and these were lined by flat, cuboidal or columnar epithelium and occasionally hobnail epithelium. There was usually a subepithelial collar of poorly differentiated cells, but the solid element of all tumors was myomatous angiomyolipoma; only one case had any adipose tissue. A dominant histological feature was the prominent lymphatic channels-identical to those of lymphangiomyomas and myomatous or triphasic AMLs. They are much more conspicuous in these cystic cases. Immunohistochemically, all tumors tested were reactive with actin, desmin and HMB-45, with the latter being more intensely positive in the subepithelial collars. Estrogen and progesterone receptors were usually positive, also. The behavior of these lesions appears to be no different from that of other AMLs.
Sixty‐five patients presenting to M. D. Anderson Hospital and Tumor Institute with Stages IE and IIE primary tonsillar lymphoma between 1954 and 1981 were reviewed. All cases were non‐Hodgkin's lymphomas, with the majority being diffuse large cell lymphoma (85%). Initial therapy was radiotherapy alone in 54 patients, radiotherapy combined with chemotherapy in 8 patients, and chemotherapy alone in 3 patients. Stage was the most important prognostic factor, with 86% and 41% 5‐year survivals for Stages IE and IIE, respectively (P = 0.006). Lymphangiography was crucial in staging patients with clinically positive cervical lymph nodes because 94% of clinically staged IIE patients developed recurrent disease, in comparison with only 50% of lymphangiogram‐staged IIE patients. The incidence of large cell lymphoma was so high as to preclude analysis of survival by histologic type. From this limited series, radiotherapy alone would appear to be sufficient initial therapy for Stage IE patients, whereas Stage IIE patients probably benefit from the addition of prophylactic chemotherapy. Relapses were most common in nonirradiated lymph‐node‐bearing areas, with the majority presenting in the first 2 years following initial therapy. The salvage of relapsing patients has been disappointing, with the best hope residing in combination chemotherapy. Cancer 53:86‐95, 1984.
Sixteen cases of a largely unrecognized benign cause for an intrascrotal mass are reported herein. These cases represent a nonneoplastic excess of native smooth muscle in the paratestis or spermatic cord growing between or around vessels or efferent ducts. The patients ranged in age from 46 to 81 years, with a mean age of 63 years. The size, available in 10 of the cases, ranged from 6 mm to 7 cm, with a mean of 2.5 cm; there was no side predilection. Microscopically, the lesions consisted of fascicles of smooth muscle, growing in a periductal, perivascular, interstitial, or mixed pattern. The cohesive, interlacing growth pattern of a leiomyoma was missing in all cases. The cause of this lesion is not apparent, although microscopic epididymal or vas deferens duct ectasia in some cases suggests a possible obstructive etiology. In any case, these are benign and without clinical significance after excision and correct diagnosis. Follow-up was available in 13 patients with no recurrences observed from 1 month to 16 years postoperatively.
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