Good syndrome is an acquired immunodeficiency due to hypogammaglobinaemia in patients with thymoma. We describe the first reported case of cytomegalovirus (CMV) retinitis due to Good Syndrome in thymic carcinoma, the second reported case of Good Syndrome in thymic carcinoma, the second reported case of bilateral CMV retinitis from Good Syndrome and the tenth reported case of CMV retinitis.
A 64 year old male presents with superior vena cava obstruction from a large anterior mediastinal mass. Biopsy confirms a squamous cell thymic carcinoma. The tumour is inoperable and he undergoes radiotherapy. A few weeks later his vision deteriorates and he is diagnosed with CMV retinitis initially unilaterally but later bilaterally. The diagnosis is confirmed by CMV DNA on vitreous sampling and plasma CMV viral load of 420 IU/mL. Peripheral blood examination reveals hypogammaglobinaemia and CD4 lymphopenia (84x10(6)) consistent with Good Syndrome.
He is treated with oral valganciclovir and intravitreal foscaranet injections and initially responds. A subsequent deterioration in vision requires treatment with IV ganciclovir and CMV IVIg. His vision improves but remains significantly below baseline. His thymic cancer remains stable on serial imaging.
There are only nine reported cases of CMV retinitis (eight unilateral and one bilateral) due to Good Syndrome - but none in thymic carcinoma. Thymomas and thymic carcinoma are distinct histologically. Thymomas are associated with a wide-range of paraneoplastic phenomenon, most commonly myasthenia gravis. In contrast, the association of paraneoplastic phenomenon with thymic carcinoma is much rarer. Administering chemotherapy to patients with Good Syndrome would be problematic.
This is only the second case described of Good Syndrome with thymic carcinoma and serves as a reminder that there are a number of paraneoplastic syndromes with thymoma and thymic carcinoma.