Curent concepts in pathology of soft tissue sarcoma

Soft tissue sarcomas (STS) constitute a heterogeneous category of soft tissue neoplasia composed mostly of uncommon tumors of diverse histology, different biology and varied outcomes. Substantial developments in immunohistochemistry (IHC), cytogenetics and molecular genetics of STS have caused a significant change in the classification and diagnosis of these tumors with a direct implication for clinical management and prognosis. In this review we discuss newer developments impacting diagnosis and prediction.

Myxoid liposarcoma: a rare soft-tissue tumor with a misleading benign appearance

Background

Lipoma is by far the most common of all benign soft-tissue tumors which far outnumber malignant tumors. Soft-tissue sarcomas are malignant tumors and are usually named for the type of tissue in which they begin. Liposarcoma (LPS), which arises in the fatty tissue, is rather an uncommon soft-tissue tumor. Multiple histologic subtypes of liposarcoma are recognized, including myxoid liposarcoma, and correspond to tumors of very different prognosis. In two-third of the cases, this tumor occurs in the muscle while often demonstrating a misleading benign appearance as observed in the majority of soft-tissue sarcomas.

Case presentation

We report the case of a 50-year-old man operated on for a fat tumor of the thigh initially diagnosed as lipoma but revealing to be a myxoid liposarcoma after histopathological examination. The initial incomplete tumor excision required the need for a re-excision with adjuvant chemotherapy and complementary radiotherapy.

Conclusion

When any suspicious soft-tissue tumor is diagnosed, the combined information gathered from accurate preoperative radiographic planning and X-rays or surgical biopsy is of tremendous value for establishing the most appropriate therapeutic program, highly adapted to the histopathological findings.

Primary liposarcoma of the lumbar spine

BACKGROUND

We describe a rare case of the cauda equina syndrome caused by a primary pleomorphic liposarcoma of the lumbar spine.

CASE REPORT

A 35-year-old man presented a 2-month history of back pain and slowly progressive weakness of lower limbs without sphincter dysfunction. It had a laminectomy for a supposed disc herniation three years previously. A diagnosis of recurrence hernia or fibrosis was discussed.

RESULTS

Magnetic Resonance Imaging (MRI) and CT scan of the lumbar vertebral column shows diffuse involvement of L4/L5 vertebral bodies, and an intradural lesion surrounding the nerve roots of cauda equina. The tumor occupied almost the whole width of the spinal canal. The diagnosis of plasmocytoma or metastasis was advocated and the patient was managed by an extended posterior approach in emergency. Histopathological findings revealed a pleomorphic liposarcoma. The patient received a course of radiotherapy and unfortunately he died at 3 months follow-up.

CONCLUSION

In spite of his unusual location in the spine, pleomorphic liposarcoma should be considered in the differential diagnosis of primary spinal tumors.

Primary liposarcoma of the thoracic spine: case report

Liposarcoma is a malignant tumor of soft tissue. The thoracic spine is an unusual location, even for metastasis, and to our knowledge, no case of primary pleomorphic liposarcoma of the vertebral body has been reported until now. A female patient presented with paraplegia. She had a previous medical history of mental depression, and complained of dorsal pain for three months following a road accident. Magnetic Resonance Imaging (MRI) revealed a collapse of T7-T8, and the diagnosis of plasmocytoma was made. She was treated with decompressive laminectomy and posterior instrumentation. Histological examination revealed a pleomorphic liposarcoma. She received a course of radiotherapy. At 13 months follow-up she developed pulmonary metastases and rib involvement. The spine is an unusual location for pleomorphic liposarcoma, even as metastasis. The differential diagnoses of this rare entity are discussed, as well as the criteria for diagnosing primary spinal liposarcoma. Although rare, our case demonstrates that liposarcoma should be considered in the differential diagnosis of spinal tumors.

Primary purely intradermal pleomorphic liposarcoma

INTRODUCTION

Pleomorphic liposarcoma (PLPS) is a high-grade pleomorphic sarcoma, containing multivacuolated lipoblasts, which usually develops during late adult life. It usually occurs in the deep soft tissues and uncommonly arises in the subcutis, the dermis representing an exceedingly rare site of occurrence.

METHODS

We describe a case of PLPS arising in the dorsal aspect of the nose of a 75-year-old woman. Preoperative duration was 9 months.

RESULTS

The lesion was intradermal well-circumscribed, dome-shaped, measuring 1.2 cm. It fulfilled the histologic criteria for inclusion in the PLPS category. The tumor cells focally expressed calretinin. A review of the literature yielded four cases documented, to which we add the present report. All the patients were adults with a mean age of 67 (range 39-95) years, and three of five cases arose on the scalp. Local recurrence occurred in one patient, but no distant metastases or disease-related deaths were observed.

CONCLUSION

PLPS very rarely arises in the dermis. In spite of high-grade morphology, the intradermal tumor shows a relatively favorable prognosis. Diagnostic consideration includes pleomorphic lipoma, clear cell atypical fibroxanthoma, balloon cell melanoma, and metastatic clear cell carcinoma of renal origin. Recognition of this distinctive and rare type of liposarcoma is essential to avoid under- or misdiagnosis and inappropriate treatment.