Background: The precise diagnostic criteria for paraneoplastic pemphigus defined by Anhalt are not always present. In many cases, the clinical and histological features are misleading.
Case report: We observed a case of paraneoplastic pemphigus in a 60-year-old man followed for low-grade inactive nodal lymphoma. The clinical course was long. The main features were lichenoid cutaneous and mucosal lesions without bullae. The only histology finding was basal vacuolization, lymphocyte infiltration and suspended keratinocyte necrosis without acantholysis. This clinical and pathological situation continued for one year. Just a few days prior to the patient's death, the clinical situation suddenly worsened with major bullae involving most of the skin surface and mucosal areas including the esophagus and respiratory tract. Cyclosporine and bolus injections of corticosteroids did not prevent the fatal outcome.
Discussion: This unusual lichenoid presentation has not been previously described. Associated skin erosions usually occur early in the disease course. The long lichenoid presentation for several months without acantholysis emphasizes the difficulties encountered in the diagnosis of paraneoplastic pemphigus. This diagnosis should be entertained in cancer patients who develop lichenoid lesions.