title: Lupus erythematosus panniculitis (lupus profundus): clinical, histopathological, and molecular analysis of nine cases.
abstract: BACKGROUND
  The diagnosis of lupus erythematosus panniculitis (LEP) may be very difficult in cases in which involvement of the subcutaneous fat is the only manifestation of the disease. The main differential diagnosis is subcutaneous panniculitis-like T-cell lymphoma (SPTCL).
  
  
  METHODS
  We performed a retrospective study reviewing the histopathologic features of 11 biopsy specimens from nine patients with LEP (M : F = 2 : 7; median age: 48 years; range: 20-71 years).
  
  
  RESULTS
  Histopathologically, all biopsies revealed a lobular panniculitis, with concomitant septal involvement in 82% of them. Dermal changes included the presence of superficial and deep infiltrates (82%) and mucin deposition (73%). The majority of cases (73%) presented also some form of epidermal involvement. The subcutaneous infiltrate was composed of lymphocytes in all cases, admixed with plasma cells in 91% of cases. Lymphoid follicles with reactive germinal centers were detected in 45% of cases. Immunohistochemistry showed a predominance of alpha/beta-T-helper and cytotoxic lymphocytes in 80% of cases admixed with B lymphocytes. The polymerase chain reaction analysis of the T-cell receptor (TCR)-gamma gene showed a polyclonal smear in all cases.
  
  
  CONCLUSIONS
  Our study shows that the most useful histopathologic criteria for distinguishing LEP from SPTCL are the presence of involvement of the epidermis, lymphoid follicles with reactive germinal centers, mixed cell infiltrate with prominent plasma cells, clusters of B lymphocytes, and polyclonal TCR-gamma gene rearrangement.
authors.affiliation: Department of Dermatology, Medical University of Graz, Graz, Austria.
authors.forename: Cesare
authors.initials: C
authors.lastname: Massone
authors.forename: Kazuo
authors.initials: K
authors.lastname: Kodama
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Salmhofer
authors.forename: Riichiro
authors.initials: R
authors.lastname: Abe
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Shimizu
authors.forename: Aurora
authors.initials: A
authors.lastname: Parodi
authors.forename: Helmut
authors.initials: H
authors.lastname: Kerl
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Cerroni
mesh_terms: D000328:Adult; D000368:Aged; D003937:Diagnosis, Differential; D005260:Female; D015334:Gene Rearrangement, gamma-Chain T-Cell Antigen Receptor / Q000276:immunology; D006801:Humans; D007150:Immunohistochemistry; D008198:Lymph Nodes / Q000276:immunology / Q000473:pathology; D008297:Male; D008875:Middle Aged; D015435:Panniculitis, Lupus Erythematosus / Q000276:immunology / Q000378:metabolism* / Q000473:pathology*; D016133:Polymerase Chain Reaction; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000235:genetics / Q000276:immunology; D012189:Retrospective Studies; D012867:Skin / Q000276:immunology / Q000473:pathology*
chemical_list: D016692:Receptors, Antigen, T-Cell, gamma-delta