Hemosiderotic Fibrohistiocytic Lipomatous Lesion

Definition

• Circumscribed fatty lesion with spindle cell component and abundant hemosiderin

Alternate Name

• Hemosiderotic Fibrolipomatous Tumor
• Proposed to be equivalent to early lesion pattern of pleomorphic hyalinizing angiectatic tumor

Diagnostic Criteria

• Variably circumscribed mass of mature fat
  • No adipocyte atypia
    • Occasional cases with focal fat necrosis
  • Cellular fibrous septa separate fat into lobules
• Bland spindle cells in septa and infiltrating fat
  • May form cellular nodules
  • Infiltration of fat may produce "honeycomb" pattern
  • No significant atypia
    • Inconspicuous nucleoli
    • Mitotic figures <1/10 hpf
• Abundant hemosiderin
  • Primarily in histiocytes in spindled areas
  • Some hemosiderin in spindled cells
• Nearly all cases in distal extremities
• Osteoclast-like multinucleated giant cells in most cases
  • Occasional cases with floret cells
• Stroma may be focally myxoid
  • Rare cases with psammoma bodies or metaplastic ossification
• Vessels occasionally have fibrin thrombi and mural hyalinization
• Scattered lymphocytes, plasma cells and mast cells
• Proposed to be equivalent to early lesion pattern of pleomorphic hyalinizing angiectatic tumor

Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342

Original posting : July 29, 2007

Supplemental studies

Immunohistology

Differential Diagnosis

Combination of bland spindle cells and fat

• Dermatofibrosarcoma protuberans
• Fibromatosis
• Atypical lipomatous tumor
• Spindle cell lipoma
• Hemosiderotic fibrolipomatous lesion

Combination of spindle cells, histiocytes and multinucleated cells

• Plexiform fibrohistiocytic tumor

Hemosiderotic Fibrohistiocytic Lipomatous Lesion	Dermatofibrosarcoma Protuberans
Fat forms mass	Infiltrates fat peripherally
Septal spindle cells	Storiform pattern
Abundant hemosiderin	Lacks hemosiderin

Both surround fat cells

Hemosiderotic Fibrohistiocytic Lipomatous Lesion	Fibromatosis
Fat forms the mass	Infiltrates fat
Abundant hemosiderin	Lacks hemosiderin
Inflammation present	Lacks inflammation

Hemosiderotic Fibrohistiocytic Lipomatous Lesion	Atypical Lipomatous Tumor, Spindle Cell Variant
Uniform size of adipocytes	Variably sized adipocytes
No lipoblasts	Lipoblasts in most cases
No significant atypia	Large atypical cells

Hemosiderotic Fibrohistiocytic Lipomatous Lesion	Spindle Cell Lipoma
Predominantly on foot and ankle	Predominantly restricted to back of neck, upper back and shoulder
Lacks ropy collagen bundles	Ropy collagen bundles
Abundant hemosiderin	Lacks hemosiderin

Hemosiderotic Fibrohistiocytic Lipomatous Lesion	Lipofibromatosis
Circumscribed	Poorly circumscribed
Prominent hemosiderin	Lacks hemosiderin
Includes histiocytes and other inflammatory cells	Histiocytes and inflammation not integral to lesion
Occasional floret cells	Lacks floret cells

plexiform fibrohistiocytic tumor pending

Clinical

• Rare, <0.2% of benign lipomatous tumors
• Age: 8 months to 74 years
• 20/23 cases on foot or ankle
  • 2 on hand
  • 1 on cheek
• History of trauma in 9/21 cases
• Recurrence (or residual tumor) 7/17 cases
  • Non-destructive
  • No metastases

Grading / Staging / Report

• Grading and Staging are not relevant
• Managerial category 1b (Recurrences do occur but are not destructive, never metastasizes)

Lists

Lipogenic tumors

• Angiomyolipoma
• Hemosiderotic Fibrohistiocytic Lipomatous Lesion
• Hibernoma
• Lipofibromatosis
• Lipoma
• Lipomatosis
• Lipoblastoma / lipoblastomatosis
• Pleomorphic lipoma
• Spindle cell lipoma
• Atypical lipomatous tumor
• Liposarcoma
  • Dedifferentiated
  • Myxoid
  • Pleomorphic
  • Unclassified

Bibliography

• Marshall-Taylor C, Fanburg-Smith JC. Hemosiderotic fibrohistiocytic lipomatous lesion: ten cases of a previously undescribed fatty lesion of the foot/ankle. Mod Pathol. 2000 Nov;13(11):1192-9.
• Browne TJ, Fletcher CD. Haemosiderotic fibrolipomatous tumour (so-called haemosiderotic fibrohistiocytic lipomatous tumour): analysis of 13 new cases in support of a distinct entity. Histopathology. 2006 Mar;48(4):453-61.
• Luzar B, Gasljevic G, Juricic V, Bracko M. Hemosiderotic fibrohistiocytic lipomatous lesion: early pleomorphic hyalinizing angiectatic tumor? Pathol Int. 2006 May;56(5):283-6.
• Folpe AL, Weiss SW. Pleomorphic hyalinizing angiectatic tumor: analysis of 41 cases supporting evolution from a distinctive precursor lesion. Am J Surg Pathol. 2004 Nov;28(11):1417-25.