title: Atypical fibrous histiocytoma of the skin with CD30 and p80/ALK1 positivity and ALK gene rearrangement.
abstract: We report the case of a two patients who presented with a solitary, asymptomatic, angiomatoid nodule on the right thigh. Histopathological finding showed a poorly circumscribed lesion, located in the dermis. The morphological aspect strongly suggested the diagnosis of atypical fibrous histiocytoma (AFH), but surprisingly, the neoplastic cells were diffusely CD30+, with a membrane staining devoid of paranuclear dot. The lesions were tested for p80/ALK1 expression. Surprisingly, we found a diffuse cytoplasmic positivity. Interestingly, using break-apart fluorescent in situ hybridization (FISH), we evidenced an ALK rearrangement in nearly 50% of the neoplastic cells. The expression of CD30 and ALK1 with ALK gene rearrangement raised the possibility of three diagnoses: a primary cutaneous anaplastic large cell lymphoma (ALCL), a cutaneous inflammatory myofibroblastic tumor (IMT), an AFH of the skin associated with ALK gene rearrangement and CD30 positivity. The three hypotheses were discussed and finally, although p80/ALK1 expression and cytogenetic abnormalities in fibrous histiocytoma (FH) are not yet reported to the best of our knowledge, we favored the diagnosis of AFH.
authors.affiliation: Departement de Pathologie, CHU Montpellier, Hôpital Gui De Chauliac, Montpellier, France.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Szablewski
authors.forename: Sara
authors.initials: S
authors.lastname: Laurent-Roussel
authors.forename: Luc
authors.initials: L
authors.lastname: Rethers
authors.forename: Antoine
authors.initials: A
authors.lastname: Rommel
authors.forename: Pascal
authors.initials: P
authors.lastname: Van Eeckhout
authors.forename: Pascal
authors.initials: P
authors.lastname: Vaneechout
authors.forename: Alessandra
authors.initials: A
authors.lastname: Camboni
authors.forename: Pascal
authors.initials: P
authors.lastname: Willocz
authors.forename: Christiane
authors.initials: C
authors.lastname: Copie-Bergman
authors.forename: Nicolas
authors.initials: N
authors.lastname: Ortonne
mesh_terms: D030301:Activin Receptors, Type II / Q000235:genetics / Q000378:metabolism*; D000328:Adult; D003937:Diagnosis, Differential; D005260:Female; D015321:Gene Rearrangement; D018219:Histiocytoma, Benign Fibrous / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D017730:Ki-1 Antigen / Q000378:metabolism*; D008297:Male; D012867:Skin / Q000378:metabolism / Q000473:pathology; D012878:Skin Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D013848:Thigh / Q000473:pathology; D055815:Young Adult
chemical_list: D017730:Ki-1 Antigen; C425364:ACVRL1 protein, human; D030301:Activin Receptors, Type II
keywords: ALK rearrangement; atypical fibrous histiocytoma; inflammatory myofibroblastic tumor; p80/ALK1 expression