https://www.ncbi.nlm.nih.gov/pubmed/32323885

2020 Apr 23. doi: 10.1111/pde.14165. [Epub ahead of print]

Primary cutaneous marginal zone lymphoma treated with doxycycline in a pediatric patient.

Abstract

We present the third reported case of a primary cutaneous marginal zone lymphoma (PCMZL) treated with doxycycline in a pediatric patient with negative serology for Borrelia burgdorferi. A 14-year-old boy presented with multiple asymptomatic erythematous papules and nodules on his extremities and trunk which biopsy confirmed to be PCMZL. He was started on doxycycline and experienced a near-complete response. Given the favorable side effect profile of doxycycline and the indolent nature of PCMZL, we believe doxycycline is a possible therapy for PCMZL pediatric patients who have widely disseminated cutaneous disease.

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**Comment**

Anyone in the Lyme world understands that a negative serology result for Bb means absolutely nothing.  The fact this young man had “near-complete response” utilizing doxy as the sole treatment can pretty much bet he had Lyme/MSIDS.

For a good read (with pictures) on PCMZL:  https://www.dermnetnz.org/topics/cutaneous-marginal-zone-lymphoma

Excerpt:

It remains unclear whether cutaneous marginal zone lymphoma is the result of a de novo neoplastic process (the beginnings of a tumour) or a reaction to exogenous and/or endogenous agents [3]. A small number of cases have been associated with Borrelia burgdorferi (the cause of Lyme disease), and hepatitis C infection [1–4].