Primary retroperitoneal spindle cell liposarcoma: Pathological and immunohistochemical findings

Abstract

Spindle cell liposarcoma (SCLS) is presently regarded as a rare variant of well-differentiated liposarcoma (WDLPS), which has the potential for aggressive clinical behavior. WDLPS occurs most frequently in the limbs and retroperitoneum. The most common site of SCLS occurrence is the upper limbs or shoulder girdle. Herein we report the first case of primary retroperitoneal SCLS. A 60-year-old Japanese man presented with a right inferior abdominal mass. Complete excision of the mass displayed a yellowish spherical tumor with a well-circumscribed appearance measuring 98 x 95 mm. Pathological examination of the tumor revealed a neural-like spindle cell proliferation set in a fibrous background that was associated with an atypical lipomatous component, which usually included lipoblasts. Mitotic cells were scarce. Immunohistochemical analysis demonstrated that lipoblasts were S100 positive, spindle cells were CD34 positive, and both spindle cells and lipoblasts were MDM2 negative. The Ki-67 labeling index was <2%. At one year follow up, the patient was alive without local recurrence or metastasis. Although the proliferative activity of this tumor did not indicate strong malignancy, retroperitoneal liposarcoma generally has a poor prognosis. Accumulation of cases of SCLS is necessary to facilitate a more accurate evaluation of the pathology and clinical behavior of this tumor.

Giant Atypical Spindle Cell Lipomatous Tumor of Retroperitoneal Origin Presenting with Lung Metastasis and Extension to the Thigh: A Case Report with Literature Review

“…8 LS is the most frequent type of STS, and includes four major histological types, including atypical lipomatous tumor/well-differentiated LS, myxoid/round cell LS, dedifferentiated LS, and pleomorphic LS. 11 Additionally, the well-differentiated LS has five variants, including sclerosing, lipoma-like, inflammatory, liposarcoma with meningothelial whorls, and spindle cell. 1 Reported initially by Weiss and Enzinger (1896), SCLS arises from a spectrum of tumors, including fibrosarcoma, intraabdominal desmoid tumor, and gastrointestinal stromal tumor.…”

The recurrent primary retroperitoneal liposarcoma

“…It was seen also by other authors. Spindle cell liposarcoma is presently regarded as a rare variant of well-differentiated liposarcoma, which has the potential for aggressive clinical behaviour (Shioi et al 2010). Dedifferentiated histological subtype and the need for contiguous organ resection was associated with an increase risk of local and distant recurrence.…”

Atypical spindle cell lipomatous tumour presenting as a large retroperitoneal mass – a case report and review of the literature

“…Of a total of 232 patients in the review by Mariño-Enriquez, only 2 cases had retroperitoneal lesions [8]. To the best of our knowledge, there are only 3 (two cases from the Mariño-Enriquez review lack individual description and were not included) previous reports of retroperitoneal ASCLT in the literature (Table I) [13][14][15].…”