RT Journal Article SR Electronic T1 Lymphocytic panniculitis: an algorithmic approach to lymphocytes in subcutaneous tissue JF Journal of Clinical Pathology JO J Clin Pathol FD BMJ Publishing Group Ltd and Association of Clinical Pathologists SP 954 OP 962 DO 10.1136/jclinpath-2014-202849 VO 68 IS 12 A1 Shiau, Carolyn J A1 Abi Daoud, Marie S A1 Wong, Se Mang A1 Crawford, Richard I YR 2015 UL http://jcp.bmj.com/content/68/12/954.abstract AB The diagnosis of panniculitis is a relatively rare occurrence for many practising pathologists. The smaller subset of lymphocyte-predominant panniculitis is further complicated by the diagnostic consideration of T cell lymphoma involving the subcutaneous tissue, mimicking inflammatory causes of panniculitis. Accurate classification of the panniculitis is crucial to direct clinical management as treatment options may vary from non-medical therapy to immunosuppressive agents to aggressive chemotherapy. Many diseases show significant overlap in clinical and histological features, making the process of determining a specific diagnosis very challenging. However, with an adequate biopsy including skin and deep subcutaneous tissue, a collaborative effort between clinician and pathologist can often lead to a specific diagnosis. This review provides an algorithmic approach to the diagnosis of lymphocyte-predominant panniculitis, including entities of septal-predominant pattern panniculitis (erythema nodosum, deep necrobiosis lipoidica, morphea profunda and sclerosing panniculitis) and lobular-predominant pattern panniculitis (lupus erythematous panniculitis/lupus profundus, subcutaneous panniculitis-like T cell lymphoma, cutaneous γ-δ T cell lymphoma, Borrelia infection and cold panniculitis).