Lymphoma and plasma cell neoplasms
T / NK cell disorders
Subcutaneous panniculitis-like T cell lymphoma

Author: Dragos Luca, M.D. (see Authors page)

Revised: 23 March 2017, last major update August 2011

Copyright: (c) 2002-2017, PathologyOutlines.com, Inc.

PubMed Search: Subcutaneous panniculitis-like T cell lymphoma [title]

Cite this page: Subcutaneous panniculitis-like T cell lymphoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/lymphomanonBsubcutaneouspan.html. Accessed June 27th, 2017.
Definition / general
Terminology
  • γδ cases are now excluded from this category and reclassified as primary cutaneous γδ T cell lymphoma (in contrast to the 3rd edition of WHO classification)
  • Most historical cases in the literature were diagnosed as histiocytic cytophagic panniculitis
Epidemiology
  • Rare, < 1% of all non-Hodgkin lymphomas
  • Slightly more common in females, median age 35 years, range 22 - 73 years
  • 20% of cases under 20 years of age
Sites
  • Multiple subcutaneous nodules on extremities and trunk
Etiology
  • Up to 20% of patients have associated autoimmune disease (most frequently SLE, with lupus profundus panniculitis)
  • No EBV
Clinical features
  • Subcutaneous nodules in extremities with associated hemophagocytic syndrome (15 - 20%)
  • Nodules range from 0.5 to several cm in diameter; larger nodules may become necrotic but ulceration is rare
  • Systemic symptoms in up to 50%
  • Cytopenias, elevated liver function tests, may have hepatosplenomegaly (nonlymphomatous), no lymphadenopathy
Case reports
Prognosis and treatment
  • Course may be aggressive or indolent; estimated 5 year survival is 80%
  • Dissemination to lymph nodes or other organs is rare
  • Poor prognosis if accompanied by hemophagocytic syndrome
  • Combination chemotherapy used traditionally; more conservative regimens (cyclosporine, prednisone, chlorambucil) may be effective
  • Much better prognosis than primary cutaneous γδ T cell lymphoma
Postulated normal counterpart
  • Mature cytotoxic αβ T cell of the adaptive immune system
Gross description
  • Subcutaneous nodules on extremities and trunk ranging from 0.5 to several cm in diameter, possibly necrotic, rarely ulcerated
Gross images

Images hosted on other servers:

Thigh

Gross, micro and immuno

Microscopic (histologic) description
  • Lesions confined to subcutis, monotonous infiltration of atypical pleomorphic lymphocytes infiltrating fat lobules, with / without sparing of the fibrous septae (resembling panniculitis)
  • Atypia varies from minimal to marked, with irregular and hyperchromatic nuclei surrounded by a rim of pale cytoplasm
  • Usually tumor necrosis / karyorrhexis, adipocyte rimming; variable vacuolated macrophages with lipid or nuclear debris, granulomatous reaction
  • No epidermal or dermal involvement (usually); not primarily angiocentric but vascular invasion possible
  • Other inflammatory cells typically absent, notably plasma cells (unlike lupus panniculitis)
Microscopic (histologic) images

Images hosted on other servers:

Various images

Rimming of fat cells


Panniculitis, rimming & karyorrhexis

Small and large
atypical
lymphocytes
rimming adipocytes

CD8+

Positive stains
Negative stains
Molecular / cytogenetics description
  • Clonal rearrangements of T cell receptor genes
  • No specific cytogenetic abnormalities reported
Differential diagnosis