What is the treatment for cutaneous plasmacytosis?

Treatment of Cutaneous Plasmacytosis

For cutaneous plasmacytosis, PUVA (psoralen plus ultraviolet A) phototherapy is the most effective first-line treatment, achieving partial to complete remission in the majority of patients. 1, 2

Initial Management Approach

PUVA phototherapy should be initiated as the primary treatment modality based on the strongest clinical evidence showing consistent responses in patients with cutaneous plasmacytosis 1, 2. Two patients in a clinicopathologic case series achieved partial remission with PUVA therapy, demonstrating its efficacy for this rare condition 1.

Alternative First-Line Options

• Topical tacrolimus ointment can be used in combination with PUVA or as monotherapy for localized lesions 2
• Topical corticosteroids may provide symptomatic relief and are appropriate for limited disease 3

Second-Line Systemic Therapies

When PUVA therapy fails or disease is extensive:

• Low-dose thalidomide has demonstrated good response in at least one well-documented case, likely functioning through decreased interleukin-6 secretion and inhibition of plasma cell growth 4. This represents a viable systemic option when phototherapy is insufficient.

• Intralesional steroid injection has been reported as an alternative approach for localized lesions 2

• Systemic chemotherapy is mentioned in the literature but should be reserved for refractory cases given the benign nature of this condition 2

Critical Diagnostic Considerations Before Treatment

You must exclude secondary causes and malignant plasma cell disorders before initiating therapy 1, 2:

• Confirm polyclonal plasma cell infiltrate on immunohistochemistry (kappa and lambda chain coexpression) 1, 2
• Rule out primary cutaneous plasmacytoma, multiple myeloma, and Waldenstrom's macroglobulinemia 3
• Check for monoclonal bands on serum protein electrophoresis and immunofixation 1
• Document hypergammaglobulinemia, which is typically present 1, 2

Treatment Algorithm

1. Confirm diagnosis with skin biopsy showing polyclonal plasma cells and exclude systemic plasma cell disorders 1, 3
2. Initiate PUVA phototherapy as first-line treatment for multiple or widespread lesions 1, 2
3. Consider topical tacrolimus for localized disease or as adjunct therapy 2
4. Switch to low-dose thalidomide if PUVA fails or is not tolerated 4
5. Reserve systemic chemotherapy only for progressive, refractory disease 2

Important Clinical Caveats

• The axilla is a characteristic site of involvement and should raise clinical suspicion for this diagnosis 1
• The clinical course is chronic and benign without spontaneous remission, so treatment is aimed at symptomatic control rather than cure 2
• Mast cell infiltrates commonly accompany the plasma cell infiltration on histopathology 1
• This condition predominantly affects Asian populations, though cases occur in other ethnicities 1, 2, 3