Rare etiology of anemia: pure red cell aplasia associated with thymoma

A 73-year-old Asian woman visited our hospital complaining of chest discomfort and dyspnea, which had worsened over the last 1 month. There was no underlying disease. The patient was diagnosed with anemia at another hospital and esophagoduodenogastroscopy was performed, confirming gastrointestinal bleeding due to a gastric ulcer. The patient improved with treatment, including endoscopic hemostasis and blood transfusion, but there was no improvement. After 1 month, no further bleeding was observed, but anemia persisted again. When the patient visited our hospital, the laboratory study revealed hemoglobin 4.1 g/dL (reference range: 12.0–16.0 g/dL), red blood cells 1.36 mil/µL (reference range: 4.2–5.4 mil/µL). A bone marrow aspiration test was performed and pure red cell aplasia (PRCA) was diagnosed. A chest X-ray revealed a right-sided mediastinal enlargement (Figure 1A). The computed tomography scan revealed a 4.6 cm enhancing mass with focal peripheral calcification in prevascular mediastinum (Figure 1B). Because PRCA with thymoma was strongly suspected, we decided to perform a thymectomy. She underwent thymomectomy and thymectomy through uniportal video-assisted thoracic surgery (Figure 1C). The thymic mass was measured as 7.0 cm × 2.8 cm × 3.2 cm and 62.2 g. The mass was diagnosed as thymoma type B1. The patient is currently under outpatient follow-up observation 3 months after surgery, and anemia has improved and is still showing signs of remission. Thymoma-associated PRCA is a rare disease associated with thymoma that may be an autoimmune phenomenon similar to myasthenia gravis (1,2). Though thymoma-associated PRCA is extremely rare, our report serves as a reminder that it might be considered in the differential diagnosis of anemia of unknown etiology.

Figure 1 Pre-operative image and intraoperative image. (A) Chest X-ray showing a right-sided mediastinal enlargement (black arrow). (B) Computed tomography showing a 4.6 cm enhancing mass with focal peripheral calcification in prevascular mediastinum (white arrow). (C) Gross image of thymoma. R, right.

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References

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