MON-339 Differential Non-Endocrinological Diagnoses of Retroperitoneal Injury: Report of 2 Cases

Introduction: Retroperitoneal tumors are rare and account for less than 0.1% of all malignant tumors. Although we find more often benign tumors, malignant variants account for 85% of tumors. Once retroperitoneum has a heterogeneous content, there are innumerable non-endocrinological differential diagnoses for these lesions, such as sarcomas (among them the liposarcoma, the leiomyosarcoma and the fibrosarcoma), lymphoma, lipomas, leiomyomas, fibromas and teratomas. Cystic lymphangioma and hibernoma may still be remembered and sought after. Among the endocrinological differential diagnoses, we mainly have: pheochromocytomas, paragangliomas and adrenal carcinomas. The 2 cases described below are examples of non-endocrine differential diagnosis of retroperitoneal lesion. Clinical Case 1: C.L.S.P, 45 years old, female, with low back pain for 1 year, with no weight changing at the analised period. She had no signs or symptoms of hyperandrogenism, hypercortisolism or hypertension, but noticed a palpable mass in the abdomen. Physical examination: palpable mass on the right flank and mesogastrium, well delimited. MRI: Heterogeneous mass, measuring 10x5.6x4 cm, hypervascularized, with cystic foci and lobulated contours, into abdominal cavity, to the right of the midline, determining compression of the below infrarenal vena cava and displacing some intestinal loops above. Laboratory tests: plasma metanephrines, urinary cortisol and cortisol, cortisol after 1mg of dexamethasone, salivary cortisol and ACTH, without changes. DHEAS, 11-deoxycortisol, androstenedione and testosterone, also without changes. Anatomopathological: Peritoneal sarcoma. Clinical Case 2: L.C.F., 42 years old, female, diabetic and hypertensive for about 20 years. She started lumbar pain, on the left, with 6 months of evolution, associated with a loss of 12 kg in the period. She had no signs or symptoms of hyperandrogenism and hypercortisolism. Physical examination with no changes. MRI: Expansive lesion occupying the left adrenal locus, with well defined margins, heterogeneous characteristics, delimiting areas of necrosis / liquefaction, as well as area suggestive of blood content, measuring 15.7x11.1x10.6 cm. Laboratory tests: plasma metanephrines, aldosterone, salivary cortisol, cortisol after 1mg of dexamethasone, urinary cortisol, ACTH, Cortisone, 21-deoxycortisol, DHEAS, Compound S, androstenedione, 17-OHP and estradiol without alterations. Anatomopathological: KIDNEY LEIOMYOSARCOMA. Immunohistochemistry: AE1 / AE3 negative, diffuse AML positive, diffuse caldemon positive, desmin negative and S100 negative. Conclusion: Thus, these differential diagnosis of retroperitoneal lesions should also be suspected by the endocrinologist.