Atypical lymphocytic lobular panniculitis: a clonal subcutaneous T-cell dyscrasia

Atypical lymphocytic lobular panniculitis (ALLP) is a recently described entity characterized by waxing and waning plaques. A morphologic and biologic continuum with subcutaneous panniculitis-like T-cell lymphoma has been suggested.

Between 2003 and 2007, we encountered five patients with ALLP. Comprehensive phenotypic and molecular studies were performed using multiplex polymerase chain reaction.

The patient population comprised four women, one man and two boys, age range of 6-42 years. All patients had a similar clinical presentation, being one of the recurrent infiltrative plaque-like lesions. All cases showed a permeation of the interstitial spaces of the subcutis by well-differentiated lymphocytes unaccompanied by significant fat necrosis. Molecular studies showed a clonal and/or oligoclonal profile in all cases. In all cases in which multiple biopsies were obtained, there was preservation of the identical T-cell clonotypes at different biopsy sites and over time. No patient progressed to lymphoma. One patient achieved remission with isotrentinoin.

ALLP represents a form of cutaneous lymphoid dyscrasia given the relatively self-limited nature of the eruption, albeit in the context of clinical recurrence.