Primary cutaneous B-cell lymphoma and B-cell pseudolymphoma may show similar clinical and microscopic presentations and sometimes represent a real diagnostic challenge for both clinician and pathologist.1
A woman on her 50s presented with a 6-month history of multiple, firm, reddish, pruritic and excoriated papules and nodules extensively distributed on the back (Figure 1). The patient was otherwise healthy, with a medical history of only fibromyalgia, and both clinical examination and blood test findings were unremarkable.
The image shows the presence of multiple firm and excoriated papules and nodules on the back (arrowheads).
Histologic examination of 2 punch biopsy specimens taken from the nodules on the back showed a prominent dermal nodular lymphoid infiltrate with germinal centers surrounded by a dense infiltrate composed of small round lymphocytes, histiocytes, mature plasma cells, eosinophils, and a smaller percentage of larger centrocyte-like cells (Figure 2). Most of the cells in the infiltrate were positive for the pan-B cell markers CD20 and CD79a. The cells in the germinal centers were also positive for CD10 and BCL6 and negative for BCL2. The small lymphocytes in the infiltrate were positive for CD3. On the basis of the overall histologic findings, a working diagnosis of primary cutaneous B-cell lymphoma of marginal zone was initially considered, but the histologic specimens were subsequently referred for a second opinion to an expert dermatopathologist. The histologic review suggested a possible differential diagnosis of cutaneous pseudolymphoma mimicking a marginal zone lymphoma, further supported by the absence of light-chain restriction by in situ hybridization.
The image shows the presence of a dense, nodular, and diffuse infiltrate in the dermis. Note the presence of germinal centers (hematoxylin-eosin, original magnification ×20).
Questioning the patient again revealed that 5 or 6 weeks prior to the onset of the skin eruption, she had undergone a course of natural therapy for chronic fibromyalgia that involved applying medicinal leeches (Hirudo medicinalis). Therefore, a favored diagnosis of pseudolymphoma secondary to the application of leeches was made.
The patient began treatment with topical mometasone furoate, applied twice daily, and complete resolution of the skin eruption was seen after 3 to 4 weeks. A monthly clinical follow-up program was subsequently commenced, and the patient had no recurrence of any inflammatory papule or nodule nor clinical or biochemical evidence of lymphoma after 15 months.
The term pseudolymphoma designates a group of reactive lymphocytic disorders that involve an inflammatory response to known or unknown stimuli simulating malignant lymphomas both clinically and histologically.2 To our knowledge only 2 cases of cutaneous multiple pseudolymphomas induced by H medicinalis have been reported.3,4 Smolle et al3 described multiple pseudolymphomas on the lower legs of a woman receiving leech therapy for venous insufficiency. More recently, Choi and Kim4 reported a similar case on the lower eyelids of a Japanese man who had infraorbital dark circles treated with H medicinalis.
Medicinal leeches have historically been used as a nonconventional treatment for chronic venous insufficiency and are now frequently used in plastic surgery.5,6 In addition, less common applications such as osteoarthritis, muscular pains, or injuries have been reported.6
In conclusion, with the increasing popularity of traditional and alternative medicine, H medicinalis therapy is becoming increasingly popular, and we all need to be aware that pseudolymphoma represents a possible complication in this type of treatment.
Corresponding Author: Davide Altamura, MD, Department of Dermatology, The Princess Alexandra Hospital Trust, Hamstel Road, Harlow, Essex CM20 1QX, England (Davide.Altamura@pah.nhs.uk).
Published Online: May 14, 2014. doi:10.1001/jamadermatol.2013.8066.
Conflict of Interest Disclosures: None reported.
Altamura D, Calonje E, Liau JL, Rogers M, Verdolini R. Diffuse Cutaneous Pseudolymphoma Due to Therapy With Medicinal Leeches. JAMA Dermatol. 2014;150(7):783-784. doi:10.1001/jamadermatol.2013.8066