EE91 / 1C1G.14
2.2.9 Lymphadenosis Cutis Benigna
Grading & Level of Importance: B
Pseudolymphoma, Borrelia lymphocytoma, Spiegler-Fendt-Sarcoid, Lymphocytic infiltration, reactive lymphoid hyperplasia.
Borrelial lymphocytoma, occurs primarily in Europe, in areas in which the Ixodes ricinus tick is endemic (Scandinavia, parts of Austria and Eastern Europe). In Europe incidence >50 cases/100,000 inhabitants/year (France 2017). Almost absent in the USA, where Borrelia burgdorferi sensu stricto is prevalent.
Harmless, reactive pseudolymphomatous infiltrate with follicular structures, which simulates cutaneous B-cell lymphoma (CBCL).
Aetiology & Pathogenesis
Causative agents: Borrelia garinii and Borrelia afzelii living in the gut of Ixodes Ricinus are transferred to the human host within 24 hours following the tick bite and induce a lymphfollicle-like inflammatory reaction.
Rare forms include reactions following herpes zoster, scabies, Hirudo medicinalis (leeches).
Signs & Symptoms
Different forms: Soft, indolent, red-blue nodules (up to 5 cm) or infiltrated plaques; mostly solitary sometimes multiple. A lupoid infiltrate is seen with diascopy (under glass slide ); occasionally with lymphadenopathy.
Sites of predilection: loose skin (ear, nipple, scrotum).
Laboratory & other workups
Borrelia IgG and IgM titers. Dermatopathology with immunochemistry. Blood cell count.
Typical B-cell pattern infiltrate, simulating an ectopic secondary (reactive antigen triggered) sharp demarcated nodular lymph follicle in the dermis, composed of small (centrocytes) and large (centroblasts) polyclonal B-lymphocytes (expression of B-cell-epitopes CD20, CD79a) and many macrophages with inclusions (tingible bodies) in the follicular center, accompanied by polyclonal (mixed kappa and lambda light chains) plasma cells and varying number of eosinophils. No monoclonal rearrangement of immunoglobulins heavy or light chains.
Often heal spontaneously within weeks or some months or following adequate treatment; in contrast to malignant CBCL.
Clinical features, serology, histology, PCR.
Prevention & Therapy
Antibiotics (doxycycline 100 mg b.i.d. for 3 weeks). Topical glucocorticosteroids may be effective (apoptosis of lymphocytes).
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