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plexiform fibrohistiocytic tumor

Tuesday 10 February 2004

plexiform myofibroblastic tumor. Ent. Enzinger, 1988. Nom. Enzinger, 1988.

Definition: Plexiform fibrohistiocytic tumor is a low-grade malignant myofibroblastic tumor of children, adolescents and young adults.

Images

- Plexiform fibrohistiocytic tumor

Synopsis

- most occur in the upper extremity (63.1-69%)
- female predominance
- ill-defined, infiltrative mass of the subcutaneous adipose tissue
- possible extension in the dermis and/or skeletal muscle
- multinodular or plexiform proliferation of mononuclear histiocyte-like cells
- spindle fibroblast-like cells
- multinucleated osteoclast-like giant cells

- three distinct growth patterns :

  • fibrohistiocytic (36%)
  • fibroblastic (32%)
  • mixed (32%)

- cellular atypia and pleomorphism rare or absent; usually less than 3 mitoses/10 HPF
- rare vascular involvement reported
- hyaline collagen
- rare myxoid changes
- +/- mucin deposits
- frequent foci of microhemorrhage
- possible osseous metaplasia
- occasional chronic inflammatory infiltrate in or around the nodules

Immunohistochemistry

- spindle cells usually express SMA and histiocyte-like cells occasionally
- histiocytic and osteoclast-like cells express CD68, spindle cells oly rarely
- unusual positivity for alpha-1-antitrypsin or alpha-1-antichymotrypsin
- occasional faint and focal CD34 and CD57 staining
- S100, desmin, cytokeratin, factor-VIII-related protein, lyzosyme, factor XIIIa negative

Variants

- myxoid plexiform fibrohistiocytic tumour (12428852)
- metastatic forms (9130995)
- devoid of osteoclast-like giant cells (12357200)

Cytogenetics

- t(8;?) (p22;?) (2164878)
- t(4;15)(q21;q15) (9973942)

Differential diagnosis

-  granulomatous inflammation

- fusiform cell soft tissue tumors

- plexiform tumors

  • plexiform neurofibroma

Prognosis

- frequent recurrence (12.5-40%) within 1-2 years after original diagnosis
- extremely rare lymph node metastases
- extremely rare pulmonary metastases

Cytogenetics

- del(X)(q13) mosaicism (21261704)

See also

- myofibroblastic tumors
- fusiform cell tumors
- plexiform tumors

References

- Plexiform Fibrohistiocytic Tumor with Molecular and Cytogenetic Analysis. Leclerc-Mercier S, Pedeutour F, Fabas T, Glorion C, Brousse N, Fraitag S. Pediatr Dermatol. 2011 Jan 25. PMID: 21261704

- Neurothekeoma and Plexiform Fibrohistiocytic Tumor: Mere Histologic Resemblance or Histogenetic Relationship? Jaffer S, Ambrosini-Spaltro A, Mancini AM, Eusebi V, Rosai J. Am J Surg Pathol. 2009 Apr 1. PMID: 19342943

- Leclerc S, Hamel-Teillac D, Oger P, Brousse N, Fraitag S. Plexiform fibrohistiocytic tumor: three unusual cases occurring in infancy. J Cutan Pathol. 2005 Sep;32(8):572-6. PMID: 16115057

- Remstein ED, Arndt CA, Nascimento AG. Plexiform fibrohistiocytic tumor: clinicopathologic analysis of 22 cases. Am J Surg Pathol. 1999 Jun;23(6):662-70. PMID: 10366148

- Salomao DR, Nascimento AG. Plexiform fibrohistiocytic tumor with systemic metastases: a case report. Am J Surg Pathol. 1997 Apr;21(4):469-76. PMID: 9130995

- Zelger B, Weinlich G, Steiner H, Zelger BG, Egarter-Vigl E. Dermal and subcutaneous variants of plexiform fibrohistiocytic tumor. Am J Surg Pathol. 1997 Feb;21(2):235-41. PMID: 9042292

- Thomazy V, Nagy A, Gal I, Nemes Z. Plexiform fibrohistiocytic tumour with novel phenotypic features. Histopathology. 1994 Aug;25(2):165-9. PMID: 7982679

- Enzinger FM, Zhang RY. Plexiform fibrohistiocytic tumor presenting in children and young adults. An analysis of 65 cases. Am J Surg Pathol. 1988 Nov;12(11):818-26. PMID: 2847569

- Salamanca J, Rodriguez-Peralto JL, Garcia de la Torre JP, Lopez-Rios F. Plexiform fibrohistiocytic tumor without multinucleated giant cells: a case report.
Am J Dermatopathol. 2002 Oct;24(5):399-401. PMID: 12357200

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