Constrictive pericarditis (CP) after allogeneic SCT may develop after infective pericarditis or pericardial GVHD. Primary effusion lymphoma (PEL), also a rare disease, is usually seen in immunocompromised patients and has a poor prognosis.We describe a case of CP and PEL developing in a patient after allo-SCT for CML. We believe it is the first documented case of these complications in this setting, and include rare FDG-PET images of PEL.A 42-year-old Italian-born man underwent a sibling allograft in 1987 for CML in chronic phase. Myeloablative conditioning was given with CY (60 mg/kg on days Ă6 and Ă5) and TBI (2 cGy twice daily on days Ă4, Ă3 and Ă2); complete donor engraftment ensued, with complete cytogenetic remission. Moderately severe chronic GVHD involving skin, oral mucosa, eyes and liver was treated with CYA, prednisolone and PUVA treatment before thalidomide was commenced, with good effect.Twenty-four months post allograft there were no other manifestations of GVHD, but he developed symptoms of pericarditis including chest pain, fever, tachycardia, hypotension and raised inflammatory markers. The electrocardiogram showed widespread ST elevation without elevation of creatine kinase MB, and chest X-ray showed a large pericardial effusion. No infective or autoimmune cause was identified and he improved with symptomatic management. Thalidomide was ceased, with no obvious immediate recurrence of GVHD.At subsequent follow --up the patient was hypotensive and complained of lethargy, dizziness and general malaise. After 6 months he developed right upper quadrant pain and abnormal liver function tests (LFTs), with alkaline phosphatase (ALP) 250 U/L (20 --175 U/L), gamma-glutamyl transferase (GGT) 550 U/L (o45 U/L) and normal transaminases and bilirubin. Ultrasound showed no cholelithiasis; liver biopsy demonstrated micronodular cirrhosis with no other specific features. Some months later, he developed ascites and peripheral oedema, managed with diuretic therapy. Symptoms and signs of chronic liver disease persisted for the next 20 years and were attributed to chronic hepatic GVHD. Cortisone acetate 37.5 mg daily caused marked improvement in appetite, energy and well being (although no improvement in LFTs), and was therefore continued despite normal adrenocorticotropic hormone levels.In 2010, 23 years post transplant, the patient deteriorated rapidly over 3 months. He was admitted to hospital with extreme lethargy, nausea, 10-kg weight loss and worsening ascites, peripheral oedema and hypotension, which did not respond to medical management.On examination he was hypotensive (systolic blood pressure 85 mm Hg), with a sinus tachycardia (100 b.p.m.) and elevated jugular venous pressure (9 cm). He had small pleural effusions, marked ascites and peripheral oedema to the groin. He was afebrile without palpable lymphadenopathy or hepatosplenomegaly.He had mild renal impairment, with creatinine level of 167 mmol/L (30 --120 mmol/L) and normal electrolytes.