Lymphocytoma cutis

Management Strategy

A skin biopsy for histopathology and immunohistochemistry is required to confirm the diagnosis, but the distinction between lymphocytoma cutis and cutaneous B-cell lymphoma may be difficult. There are no agreed histologic criteria; however, features that suggest lymphocytoma cutis include an unaffected epidermis, separated by a grenz zone, below which are well-formed, non-expanded, reactive germinal centers. The majority of the infiltrate consists of small, round B-lymphocytes with admixed T-cells (usually <30%), without cellular atypia, and polytypic expression of kappa and lambda light chains. A further feature is the presence of numerous tangible-body macrophages within the lymphoid follicles. Molecular analysis of the immunoglobulin heavy chain gene has shown that a significant proportion harbor B-cell clones, which suggests that many cases previously thought to be lymphocytoma cutis represent indolent, low-grade, primary cutaneous B-cell lymphomas (PCBCL). In cases where the diagnosis is in doubt, including those with unusual manifestations, such as multiple nodules, monotypic expression of immunoglobulin light chains, or the detection of B-cell or T-cell clonality by molecular techniques, careful evaluation to exclude systemic disease (a thorough clinical examination, thoracoabdominopelvic computed tomography [CT] scan, or positron emission tomography (PET) scan) is required, with adequate long-term follow-up.

A history of possible stimuli known to cause lymphocytoma cutis should be sought; these include Borrelia burgdorferi infection, Leishmania infection, trauma, vaccinations, allergy hyposensitization injections, drugs, arthropod bites, acupuncture, gold pierced earrings, tattoos, treatment with leeches (Hirudo medicinalis) , and post-herpes zoster scars, but in most cases the etiology is unknown.

The course of the disease varies but tends to be chronic and indolent; some lesions may resolve spontaneously without treatment. There is no therapy of proven value for lymphocytoma cutis, with only anecdotal case reports and small series reported and no clinical trials in the literature.

If a cause can be identified, the causative agent should be removed. If infection with B. burgdorferi is suspected, treatment with appropriate antibiotics (for adults: doxycycline 100 mg twice per day, or amoxicillin 500–1000 mg three times per day for 21 days, or, alternatively azithromycin 500 mg once daily for 17 days; doses vary for children depending on age and weight) should be initiated.

Localized disease can be treated by simple excision and may respond to intralesional injection of corticosteroids , local irradiation , or intralesional interferon-α. More widespread (generalized) disease is traditionally treated with oral antimalarials, most commonly hydroxychloroquine (maximum dose 6.5 mg/kg/day); however, lesions may fail to respond to treatment or may recur after cessation of therapy. Other treatment modalities include subcutaneous interferon-α and oral thalidomide . Effective responses to destructive therapies, including cryotherapy and the argon laser , have been reported. A subtype of generalized lymphocytoma cutis may be exacerbated by light, and therefore sun avoidance and the use of sun block are important.