Osteolipoma of knee: a rare case report

Arnab Chaudhuri,Dipanwita Nag,Aparajita Samaddar,Ira Mondal,Nandini Das

doi:10.21276/aabs.2017.1320

Abstract

Lipomas are the most common benign soft tissue tumors and appear in any part of the body. They typically consist of mature adipose tissue. Osteolipoma is an extremely rare histologic variant of lipoma that contains mature lamellar bone within the tumor and osteolipoma independent of bone tissue are very rare. We report a case of histologically confirmed osteolipoma independent of bone located just above left knee. A 61 year old female presented with medial sided left knee pain of 6 month duration. X-ray demonstrated a partially calcified 3.5 cm diameter mass located in anterior to the distal medial femur. Histologic examination of an excisional biopsy showed the lesion to be an osteolipoma. Osteolipoma is a rare histologic variant of lipoma with osseous metaplasia, but should be considered in the differential of a fat-containing neoplasm with ossification. DOI: 10.21276/AABS.2017.1320

Highlights

Lipoma is a common benign soft tissue neoplasm that sometimes may have mixed tissue components
6 cases of osteolipoma arising in connection with knee joint have been described [3]
We present a case of an osteolipoma in the left knee region

Summary

Introduction

Lipoma is a common benign soft tissue neoplasm that sometimes may have mixed tissue components. Lipomas with mixed components are named according to the type of tissue. Ossification of a lipoma was first described in 1959, and it is rarely reported [1, 2]. 6 cases of osteolipoma arising in connection with knee joint have been described [3]. We present a case of an osteolipoma in the left knee region. A 61-year-old female presented with a proximal left knee mass. The patient reported pain along the medial aspect of the knee for the past 6 month, with recent notice of a palpable mass. Radiographs revealed a calcified mass anterior to the distal left medial femur in the region of the suprapatellar fossa. (Fig.1B) Histologic examination revealed mature adipose tissue in which a large fragment of cortical-type bone was embedded.

Discussion

Conclusion