Indian Journal of Pathology and Microbiology

LETTER TO EDITOR
Year
: 2009  |  Volume : 52  |  Issue : 2  |  Page : 284--285

Chondroid lipoma: A pseudosarcomatous tumor of soft tissues


Sunitha Jacob, Debahuti Mohapatra 
 Department of Pathology, Christian Medical College and Hospital, Ludhiana, India

Correspondence Address:
Sunitha Jacob
Department of Pathology, Christian Medical College and Hospital, Ludhiana
India




How to cite this article:
Jacob S, Mohapatra D. Chondroid lipoma: A pseudosarcomatous tumor of soft tissues.Indian J Pathol Microbiol 2009;52:284-285


How to cite this URL:
Jacob S, Mohapatra D. Chondroid lipoma: A pseudosarcomatous tumor of soft tissues. Indian J Pathol Microbiol [serial online] 2009 [cited 2022 May 26 ];52:284-285
Available from: https://www.ijpmonline.org/text.asp?2009/52/2/284/48952


Full Text

Sir,

Tumors of adipose tissue are among some of the most common soft tissue tumors encountered by the pathologist. Most of these are conventional lipomas and pose no diagnostic confusion. However, some variants like spindle cell lipoma, pleomorphic lipoma and lipoblastoma are frequently misdiagnosed as sarcoma. [1] Chondroid lipoma is another unique variant of lipoma characterized by a complex and rather bewildering histomorphology, thus further adding to the burgeoning list of pseudosarcomatous soft tissue lesions. [1],[2]

A 38-year-old female presented with a gradually enlarging, painless, mass in the right upper thigh, which was noticed 4 months ago. The mass was subcutaneous in location, well defined and nontender. The overlying skin was normal. The mass was excised in toto.

The mass measured 4 × 3 × 2cm; it was well encapsulated and had a predominantly bright yellow cut surface interspersed with small pale white foci. Microscopic examination displayed an encapsulated tumor composed of small, round cells disposed in loose sheets, groups and cords laid out in abundant loose myxo-hyaline and chondroid matrix [Figure 1]. The cells possessed uni- or multi- vacuolated cytoplasm, which showed positivity for fat and glycogen by oil red-O and PAS stains, respectively. The nuclei were mildly pleomorphic, with low mitotic activity and showed indentation of their margins by the cytoplasmic vacuoles [Figure 2]. The cytonuclear morphological features thus imparted to the cells a striking resemblance to lipoblasts or chondroblasts. In some fields, groups and small sheets of mature fat cells were also present. Tumor vascularity was low and there was no plexiform capillary network. A diagnosis of chondroid lipoma was made.

Chondroid lipoma is an unusual benign lipomatous tumor first described as a distinct entity by Meis and Enzinger [1] in 1993. The vast majority of chondrolipomas occur in females and is seen between ages of 14 and 70 years (median of 36 years). [1] It typically presents as a slow growing painless mass in the subcutaneous tissue, superficial muscular fascia or skeletal muscles. The tumor is mostly located in the proximal extremities and limb girdles and occasionally over the trunk and head and neck region. [1],[2] Rare cases have been reported in the oral cavity and within myometrial leiomyoma. [3],[4]

The quintessential features of chondroid lipoma are sheets, nests and cords of small uniform vacuolated round cells mimicking lipoblasts or chondroblasts suspended within a chondromyxoid matrix. The cell cytoplasm is rich in glycogen and neutral fat. The nuclei are small with inconspicuous nucleoli. Variable numbers of mature adipocytes and few small caliber vessels are scattered about. The tumor is devoid of the typical plexiform capillary pattern seen in myxoid liposarcoma. Perivascular fibrosis and small thrombi may be seen in some cases. Immunohistochemistry reveals positivity of the small cells for vimentin and S 100 protein, variable staining with cytokeratin and CD68 antigen and negativity for EMA, HMB 45 and smooth muscle actin. [1],[2]

Kindblom [2] states that chondroid lipoma has a unique cell population with features of both embryonal fat and embryonal cartilage implying a close relationship between adipose tissue and cartilage. The female predominance of chondroid lipoma raises the possibility of hormonal factors in its pathogenesis. [1]

Excision of the tumor is curative with no recurrence, metastasis or malignant transformation. [1],[2] The importance of this rare tumor lies in its complex histology which is often mistaken for myxoid liposarcoma, extra-skeletal myxoid chondrosarcoma, soft tissue chondroma and chondrolipoma. Although chondroid lipoma shares with myxoid liposarcoma the features of lipoblasts, myxoid matrix, circumscription and deep location, it lacks the characteristic delicate plexiform vascular network, whereas chondroid stroma is absent in the latter. Both extraskeletal myxoid chondrosarcoma and chondroid lipoma have intracellular glycogen and hyaluronidase resistant acid mucopolysaccharide matrix; however, chondrosarcoma features distinct lobulation, lacks adipocytes and has sparse or no intracytoplasmic vacuoles. [1] Soft tissue chondroma primarily arises in hands and feet and is characterized by true hyaline cartilage and absence of fat vacuoles. Chondrolipoma is composed of mature hyalinized cartilage, adipose tissue and myxoid matrix but lacks lipoblast-like cells. [5]

In conclusion, chondroid lipoma is a rare, benign, unique lipomatous tumor of diagnostic importance because of its complex pseudosarcomatous histology. Lack of awareness of this tumor may lead to a serious erroneous diagnosis of soft tissue sarcoma.

References

1Meis JM, Enzinger FM. Chondroid lipoma: A unique tumor ­simulating liposarcoma and myxoid chondrosarcoma. Am J Surg Pathol 1993;17:1103-12.
2Kindblom LG, Meis-Kindblom JM. Chondroid lipoma: An ultrastructural and immunohistochemical analysis with further observations regarding its differentiation. Hum Pathol 1995;26:706-15.
3Darling MR, Daley TD. Intraoral chondroid lipoma: A case report and immunohistochemical investigation. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2005;99:331-3.
4Blandamura S, Florea G, Chiarelli S, Rondinelli R, Ninfo V. ­Myometrial leiomyoma with chondroid lipoma-like areas. Histopathology 2005;46:596.
5Lakshmiah SR, Scott KW, Whear NM, Monoghan A. Chondroid lipoma: A rare but diagnostically important lesion. Int J Oral Maxillofac Surg 2000;29:445-6.