Soft tissue
Fibrohistiocytic tumors
Malignant fibrous histiocytoma of soft tissue - inflammatory

Author: Vijay Shankar, M.D. (see Authors page)

Revised: 16 September 2016, last major update August 2012

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PubMed Search: Malignant fibrous histiocytoma of soft tissue - inflammatory

Cite this page: Malignant fibrous histiocytoma of soft tissue - inflammatory. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/softtissuemfhinflam.html. Accessed December 10th, 2016.
Definition / General
  • Neoplastic histiocyte-like cells mixed with, and often obscured by neutrophils and other inflammatory cells
Terminology
  • Most of these tumors are probably dedifferentiated liposarcoma (J Pathol 2004;203:822, see also Pathol Int 1997;47:642) or leiomyosarcoma
  • Diagnosis of exclusion; recommended to take many sections and use immunohistochemistry to rule out mimics
Clinical Features
  • Very rare, usually age 40+ years, often retroperitoneal
  • May be associated with fever, leukocytosis (leukemoid reaction) and eosinophilia
  • May occur in skin with predominance of lymphocytes (Am J Dermatopathol 2002;24:251)
  • Very aggressive with poorest prognosis of all MFH types (2/3 die of disease, 1/4 have distant metastases) although these studies probably included other morphologically similar disorders
Case Reports
Gross Description
  • 8 - 10 cm, yellow due to xanthoma cells; firm, lobulated
Micro Description
  • Commonly has storiform pattern, background of inflammatory cells (histiocyte-like, xanthoma, neutrophils, lymphocytes, eosinophils, plasma cells) which may obscure tumor cells
  • Tumor cytoplasm may contain phagocytized neutrophils; nuclei are large and vesicular with prominent nucleoli
  • May have bizarre giant cells or atypical mitotic figures but no necrosis
Micro Images

Images hosted on PathOut servers:

Acute inflammatory cells and large histiocyte-like cells

Numerous histiocyte-like cells resembling lymphoma

Large histiocyte-like cells with
prominent nucleoli resembling lymphoma
or carcinoma, with variable fibroblasts





Case of the Week #144 - abdominal tumor



Images hosted on other servers:

H&E, CD68, vimentin

Cytology Description
Positive Stains
Molecular / Cytogenetics Description
  • 12q13-15 amplification or gain (these cases may actually be dedifferentiated liposarcoma)
Differential Diagnosis