No abstract

Introduction: Patients with cardiac amyloidosis light chain (AL) present with negative Tc-99m pyrophosphate (PYP) scintigraphy (absent or mild heart uptake). On the contrary, patients with cardiac amyloidosis transthyretin (ATTR) present with positive Tc-99m PYP scanning (intensive heart uptake). We present a false positive Tc-99m PYP scintigraphy (grade 2, the heart-to-contralateral ratio is 1.65) in a patient with AL. Patient concerns: A 42-year-old Chinese man complained of effort intolerance, chest discomfort, and short of breath progressively over 1 year. New York Heart Association Class III. Physical examination showed legs swelling. Laboratory revealed elevated brain natriuretic peptide of 23,031 ng/mL (0–88) and Troponin-T of 273.4 ng/mL (0–14). Diagnosis: Cardiac amyloidosis light chain. Evidences: free light chains (FLCs): decreased serum free kappa/lambda ratio of 0.043 (0.31–1.56). Immunofixation electrophoresis: a positive lambda light chain monoclonal protein. Cardiac biopsy: HE: Ambiguity Congo red strain. Myocardial immunofluorescence: positive lambda light chain. Myocardial immunohistochemistry: positive lambda light chain, negative kappa light chain, and TTR. Interventions: Furosemide 40 mg qd, torasemide 20 mg qd, spirolactone 20 mg qd, potassium chloride 10 mL per 500 mL urine, atorvastatin calcium tablet 20 mg qd, aspirin enteric-coated tablets 100 mg qd during the 2-weeks in-hospital. Outcomes: The patient died 2 months later after discharge. Conclusion: False positive Tc-99m PYP scintigraphy may rarely presented in patients with cardiac amyloidosis light chain. So, the clonal plasma cell process based on the FLCs and immunofixation is a base to rule out AL cardiac amyloidosis when we interpret a positive Tc-99m PYP scintigraphy.

Langerhans cell histiocytosis only involving the posterior elements of the spine is rare. We report the case of a 7-year-old boy who has pain and restricted motion of his neck. 18F-FDG PET/CT revealed an osteolytic lesion in the posterior elements of the fourth cervical vertebra. The lesion has high 18F-FDG uptake with an SUVmax of 8.01. An operation was performed, and the final pathological finding revealed Langerhans cell histiocytosis.

Primary pulmonary diffuse large B-cell lymphoma is a rare type of extranodal lymphoma with PET/CT manifestations of consolidations, ground-glass opacities, and high 18F-FDG uptake. Because of its rarity and the lack of typical imaging features, it can hardly be diagnosed through PET/CT. The central cavitation was occasionally seen in pulmonary diffuse large B-cell lymphoma and may be a key imaging feature in differential diagnoses. In this report, we describe an 80-year-old man diagnosed as having pulmonary diffuse large B-cell lymphoma, which demonstrated the central cavitation detected by 18F-FDG PET/CT.