FDG PET/CT in Detection of Metastatic Involvement of Heart and Treatment Monitoring in Non-Hodgkin's Lymphoma.

Cardiac metastasis occurs in up to a quarter of patients with metastatic cancer and is seen most commonly in melanoma and lymphoma. Metastatic involvement of the heart and pericardium may go unrecognized until autopsy. We describe a patient of non-Hodgkin's lymphoma detected to have involvement of right atrium on F-18 FDG PET/CT and monitoring of response to chemotherapy.

Introduction

Cardiac metastasis is not uncommon. The clinical findings of cardiac metastasis are often non-specific. On the other hand it is important to detect early any metastasis to life threatening sites like heart, brain, spinal cord, etc; so that prompt therapeutic interventions could be made to reduce morbidity and mortality. FDG PET/CT is widely used in the diagnostic evaluation and staging of different malignant tumors. The technique has also proven to be extremely useful in treatment monitoring.

Case Report

A 73-year-old female patient presented with abdominal pain and swelling in right infra clavicular region. Abdominal ultrasonography was normal. Upper GI endoscopy revealed whitish plaques in the esophagus with bulging papillae in second part of duodenum, which raised the suspicion of GI malignancy. FNAC from the right infraclavicular swelling was suggestive of reactive lymphoid hyperplasia. Whole body MRI revealed one T2 hyperintense lesion in right thyroid lobe, two solid nodules in right breast and a few well-defined, rounded, hyperintense lesions in head of both the humeri and D12-L2 vertebral bodies. Thyroid scan showed cold nodule in the right lobe of thyroid gland. Due to indeterminate nature of the lesions, F18-FDG PET/CT was performed [Figure 1]. Maximum intensity projection (A) of F18-FDG PET/CT study revealed intensely FDG-avid soft tissue mass in the right breast tissue, FDG avid cervical, right supraclavicular, right axillary, mediastinal and abdominal lymph nodes. Intense FDG uptake in a filling defect of size 2.6 × 2.0 cm in the right atrium (arrow) was also noticed (A). Transaxial fused PET/CT image (C) showed intensely FDG avid right atrial lesion (arrow) and soft tissue density in the right breast. Overall features of PET scan were suggestive of lymphoma or primary in right breast with metastases. Biopsy from the right supraclavicular lymph node was positive for diffuse large B-cell lymphoma (DLBCL). Repeat PET/CT scan (B) after two cycles of chemotherapy (R-CHOP) showed complete resolution of FDG avidity in the breast, heart and bone lesions. Mild FDG uptake was noted in a few cervical and right axillary lymph nodes suggestive of significant metabolic response. Transaxial fused PET/CT image after two cycles of chemotherapy (D) also showed complete resolution of FDG avidity in the breast and heart.

Figure 1

F18-FDG PET/CT study (a) maximum intensity projection showing intensely FDG-avid soft tissue mass in the right breast tissue, FDG avid cervical, right supraclavicular, right axillary, mediastinal and abdominal lymph nodes. Intense FDG uptake (arrow) in the region of right atrium is also noticed. Transaxial-fused PET/CT image (c) showed intensely FDG avid right atrial lesion (arrow) and soft tissue density in the right breast. Repeat PET/CT scan (b) after 2 cycles of chemotherapy showing complete resolution of FDG avidity in the breast, heart and bone lesions. Mild FDG uptake is noted in a few cervical and right axillary lymph nodes suggestive of significant metabolic response. Transaxial-fused PET/CT image after two cycles of chemotherapy (d) also showed complete resolution of FDG avidity in the breast and heart

Cardiac metastasis occurs in up to a quarter of patients with metastatic cancer and is seen most commonly in melanoma and lymphoma.[1] Often, the diagnosis is not made until autopsy. Secondary cardiac lymphomas are found in approximately 10–30% of lymphoma patients in autopsy studies.[2] Most cases are B-cell lymphomas and present with cardiac involvement fairly late in the course of the disease.[3] Metastases to the heart and pericardium are generally associated with a poor prognosis.[4-6] Overall, cardiac lymphoma remains a difficult diagnosis. Serial PET has been suggested to be more accurate than MRI and echocardiography for assessing cardiac lymphoma regression.[7] In literature a few case reports have shown the pattern of involvement of metastatic involvement of the heart in non-Hodgkin's lymphoma.[89] We describe a unique case where FDG Pet allowed early diagnosis, prompt treatment and monitor response to chemotherapy of cardiac lesion, thus leading to the resolution of heart lesion before the occurrence of any cardiac complications.