Avid expression of the SSTR on Ga-DOTATATE PET-CT/Tc-HYNIC-TOC scintigraphy in non-I-concentrating metastatic differentiated thyroid cancer is observed in a relatively low fraction of patients that could favor the feasibility of Lu-DOTATATE therapy. Although seen in a small fraction, taking into account that no treatment exists in this group, somatostatin receptor-targeted imaging can be an alternative diagnostic modality in the therapeutic decision making with peptide receptor radionuclide therapy and monitoring. The documentation of elevated serum chromogranin A level in 3 patients with intense tracer uptake could suggest a possible neuroendocrine differentiation in the affected tissues leading to the expression of chromogranin A along with SSTR-avid expression. This observation needs to be explored in future studies. No definite conclusions can be drawn on the therapeutic efficacy of the Lu-DOTATATE therapy in this group at present, and more prospective research is required in this area.

Erdheim–Chester disease is a rare disease with systemic non-Langerhans cell histiocytosis, the diagnosis of which with conventional imaging modalities is challenging. We describe a case of a 73-year-old woman who was referred with a progressive history of bilateral proptosis. The magnetic resonance imaging (MRI) orbit demonstrated bilateral orbital masses with optic nerve encasement. A subsequent 18F-FDG PET/CT scan showed multi-organ disease with involvement of the orbits, pericardium, aorta, pararenal fascia, and appendicular bones. Metabolically active, easily accessible areas were selected for CT-guided biopsy. The biopsy showed sheets of foamy histiocytes with the expression of CD 68 and CD 163 consistent with a diagnosis of Erdheim–Chester disease. The FDG PET/CT played a pivotal role in establishing the diagnosis with the assessment of disease extent and further guided in the targeted biopsy.

A man in his 60s developed reactive arthritis following treatment with intravesical Bacillus Calmette-Guerin (iBCG) for papillary carcinoma of bladder. Evaluation revealed leucocytosis and raised inflammatory markers. HLA B27 was positive. Based on the temporal relationship, it was attributed to BCG-related reactive arthritis. iBCG was stopped. Treatment with non-steroidal anti-inflammatory drugs (NSAIDS) and glucocorticoids were ineffective. Prolonged course of disease-modifying antirheumatic drugs (DMARDS) was required which aided in alleviation of symptoms and sustained remission. Intravesical BCG therapy is a treatment for bladder cancer. It is rarely associated with reactive arthritis, which responds to discontinuation of iBCG and treatment with NSAIDS and/or short-term glucocorticoids. iBCG-related reactive arthritis commonly has an acute/subacute course. Chronic arthritis as observed in our case requiring prolonged treatment with DMARDS is rare.