Good’s syndrome (hypogammaglobulinemia with thymoma) presenting intractable opportunistic infections and hyperkeratotic lichen planus

Good’s syndrome (GS) is a rare acquired combined T‐ and B‐cell immunodeficiency accompanying thymoma. This report concerns a case of a 57‐year‐old man with GS manifesting intractable opportunistic infections and hyperkeratotic lichen planus. He had a past history of extended thymectomy for removal of thymoma. He consulted us about scaly and exudative intractable erythematous plaque on his right forearm. The histology was compatible with phlegmon coexisting with lichen planus. Laboratory examination results indicated hypogammaglobulinemia accompanied by complete absence of B cells, which is consistent with GS. Combined treatment with immunoglobulin replacement and administration of antibiotics and antifungal drugs was effective for the phlegmon and overlying fungal infection. The patient also presented with hyperkeratotic lichen planus on both knees and the right elbow, suggesting that intractable opportunistic infection and lichen planus may be associated with GS.