Fibroblastic rheumatism: fibromatosis rather than non-Langerhans cell histiocytosis.
BACKGROUND
Fibroblastic rheumatism is a unique fibro-proliferative disease affecting the skin and joints. It is characterized by distinctive clinical and histological features related to benign spindle-shaped cells proliferation. Pediatric reports are scarce in the literature.


OBJECTIVE
We describe here a new case in a 10-year-old boy and discuss the potential origin of the cell proliferation.


METHODS
Clinical findings, radiology, microscopic examination and outcome are reviewed. Histopathology and immunochemistry studies were performed on skin biospies using CD68, CD163, desmin, factor XIIIa, CD34, smooth muscle actin, PS100, epithelial membrane antigen, and calponin.


RESULTS
Histological sections disclosed a rather circumscribed nonencapsulated nodular infiltrate, invading the dermis and the upper subcutaneous tissue, consisted of a proliferation of spindle or stellate-shaped cells and thickened collagen fibers. Orcein staining showed disappearance of the elastic network. Aponeurosis and muscle were normal. A mild perivascular lymphohistiocytic infiltrate was noted. Calponin-staining was less strongly expressed as SMA, and some of them but not all were CD68 positive, as well. On the other hand, all were CD34, CD163, FXIIIa, PS100, EMA and desmin-negative.


CONCLUSIONS
The true origin of these cells remains unclear. Some authors have speculated a histiocytic origin. However, immuno-chemical staining in our case failed to confirm this hypothesis and instead supported a fibroblastic/myofibroblastic origin. Given the clinical course and the histological and immunohistochemical results, we suggest that FR should be added to the group of fibromatoses.
Kluger
Nicolas
N
Department of Dermatology, Hôpital Saint-Eloi, CHU Montpellier, University of Montpellier I, Montpellier, France.
Dumas-Tesici
Alexandra
A
Hamel
Dominique
D
Brousse
Nicole
N
Fraitag
Sylvie
S
D002648:Child; D003937:Diagnosis, Differential; D005347:Fibroblasts / Q000473:pathology*; D005350:Fibroma / Q000188:drug therapy / Q000473:pathology*; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D008297:Male; D008727:Methotrexate / Q000627:therapeutic use; D011239:Prednisolone / Q000627:therapeutic use; D012216:Rheumatic Diseases / Q000188:drug therapy / Q000473:pathology*; D012867:Skin / Q000473:pathology*; D012878:Skin Neoplasms / Q000188:drug therapy / Q000473:pathology*; D016896:Treatment Outcome
D007166:Immunosuppressive Agents; D011239:Prednisolone; D008727:Methotrexate