Large retroperitoneal atypical spindle cell lipomatous tumor, an extremely rare neoplasm: A case report

Abstract

BACKGROUND Atypical spindle cell lipomatous tumor (ASLT) is a rare soft tissue neoplasm with a low potential for malignancy. ASLT frequently occurs in the limb and limb girdles. However, large retroperitoneal ASLTs are extremely rare. There was no concrete case report of retroperitoneal ASLTs. CASE SUMMARY An 18-year-old woman presented with abdominal pain and a palpable mass. Abdominal computed tomography revealed a large fatty mass that was approximately 30 cm in size and filled the entire abdominal cavity. Surgical excision was indicated. The tumor did not invade the adjacent organs. The pelvic cavity was then too narrow to dissect smoothly. The mass was successfully excised without tumor rupture or adjacent organ injury. Microscopically, the neoplasm was a well-differentiated adipocytic neoplasm. Immunohistochemical staining showed that the spindle cells were positive for CD34 and desmin, in addition to multifocal positivity for S100 protein. These histological features were consistent with an ASLT. The patient’s postoperative course was uneventful. At the 12-mo follow-up, no evidence of recurrence or metastasis was observed. CONCLUSION To the best of our knowledge, our study is the first concrete report of a large retroperitoneal ASLT in the English literature. In the large retroperitoneal ASLT located in the pelvic cavity, which made it too narrow and tight to dissect, complete excision is difficult but very important because of recurrence risk. Although large retroperitoneal ASLTs are considered extremely rare, their detection is important for accurate evaluation and management. Owing to their significant rarity, retrospective multicenter case studies are required to determine the clinicopathologic characteristics.

Case report: Atypical spindle cell/pleomorphic lipomatous tumor masquerading as a myxoid liposarcoma or intramuscular myxoma

“…In general, the T1 intensity on MRI is important for differentiating lipomatous tumors ( 16 ); therefore, we focused on the intensity of T1-weighted images (only CT was available in one case). Based on the results of three previous cases, the T1 intensity of ASPLT can be divided into three groups: (i) high ( 7 ), (ii) high and low ( 6 ), and (iii) low ( 8 ). ASPLT and SCL tend to have similar enhancement patterns on T1-weighted images, which reflect their similar pathological findings ( 19 ).…”

“…Accordingly, histopathology, immunohistochemistry (IHC), and fluorescence in situ hybridization (FISH) are indispensable for an accurate diagnosis (4,5). Although there have been few reports on the magnetic resonance imaging (MRI) findings of ASPLT, ASPLTs have varying T1 intensities, which may reflect their pathological diversity (6)(7)(8). Herein, we report a case of ASPLT masquerading as a myxoid tumor and review the pathological and MRI findings of ASPLT.…”

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].…”

Tailored Physical Therapy in a Case of Tenotomy Post Hip Flexion Deformity With Structural Scoliosis: A Case Report

“…Spindle cell tumours are rare soft tissue neoplasms with a low potential for malignancy. Atypical spindle cell tumours frequently occur in the limbs and limb girdles [ 4 ]. The posterior margins of these tumors frequently overlap the psoas muscle and retroperitoneal fat, making attaining negative margins difficult without visibility and precise dissection [ 5 ].…”