Case of the Month

53 year old woman presents with an enlarging, non-tender nodule on her scalp x 3 years. Her CBC, LFT’s, Chem panel and lipid panel were are normal.

Diagnosis: The lesion was biopsied and found to be a: Lipidized fibrous histiocytoma

I received the pathology report and micrographs from Erick Jacobson-Dunlop and his partner Andrew Larson, exceptional dermatopathologists!

Reference and Information:

Am J Dermatopathol. 2000 Apr;22(2):126-34.

Lipidized fibrous histiocytoma: clinicopathologic analysis of 22 cases.

Iwata J1, Fletcher CD.

AUTHOR INFORMATION

1Department of Pathology, Kochi Medical School, Japan.

ABSTRACT

We report the clinicopathologic analysis of 23 tumors from 22 patients with lipidized fibrous histiocytoma (FH), which has been an underrecognized variant of cutaneous FH. The 16 men and 6 women patients (male/female ratio, 2.7:1) ranged in age from 21 to 82 years (median, 50 years). The location of the tumor was concentrated strikingly in the lower limb, especially around the ankle, hence the alternative informal designation of "ankle-type" FH. The tumors showed relatively large size compared with those of conventional FH, ranging up to 8 cm in greatest dimension (median, 2.5 cm), and tended to be polypoid and yellowish in color. Hyperlipidemia was only a rare and perhaps incidental association in two cases. Histologically, lipidized FH was characterized by accumulation of numerous foam cells, smaller numbers of siderophages, and stromal hyalinization typically appearing "wiry," keloidlike, or osteoidlike, although focal features of ordinary FH almost always coexisted and were identified as a focal storiform or curlicue pattern of spindle tumor cells, epidermal hyperplasia, and peripheral "entrapped" dermal collagen. Although follow-up data are limited, the prognosis appears to be good with no recurrence, even after incomplete excision. These clinicopathologic features highlight lipidized FH as a distinctive variant, which can be distinguished from ordinary or other variants of FH, as well as from other foam cell-rich cutaneous lesions, especially xanthoma.