Pneumonitis is an uncommon but potentially fatal toxicity of anti-programmed death-1 (PD-1)/ programmed death ligand 1 (PD-L1) monoclonal antibodies (mAbs). Clinical, radiologic, and pathologic features are poorly described. MethodsPatients who received anti-PD-1/PD-L1 monotherapy or in combination with anti-cytotoxic T-cell lymphocyte-4 mAb were identified at two institutions (Memorial Sloan Kettering Seventy-two percent (31 of 43) of cases were grade 1 to 2, and 86% (37 of 43) improved/resolved with drug holding/immunosuppression. Five patients worsened clinically and died during the course of pneumonitis treatment; proximal cause of death was pneumonitis (n = 1), infection related to immunosuppression (n = 3), or progressive cancer (n = 1). Radiologic and pathologic features of pneumonitis were diverse. ConclusionPneumonitis associated with anti-PD-1/PD-L1 mAbs is a toxicity of variable onset and clinical, radiologic, and pathologic appearances. It is more common when anti-PD-1/PD-L1 mAbs are combined with anti-cytotoxic T-cell lymphocyte-4 mAb. Most events are low grade and improve/ resolve with drug holding/immunosuppression. Rarely, pneumonitis worsens despite immunosuppression, and may result in infection and/or death.

Monoclonal antibodies (mAb) targeting immune checkpoint pathways such as cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed death 1 (PD-1) may confer durable disease control in several malignancies. In some patients, immune checkpoint mAb cause cutaneous immune-related adverse events. Although the most commonly reported cutaneous toxicities are mild, a subset may persist despite therapy and can lead to severe or life-threatening toxicity. Autoimmune blistering disorders are not commonly associated with immune checkpoint mAb therapy. We report a case series of patients who developed bullous pemphigoid (BP), an autoimmune process classically attributed to pathologic autoantibody formation and complement deposition. Three patients were identified. Two patients developed BP while receiving the anti-PD-1 mAb nivolumab, and one while receiving the anti-PD-L1 mAb durvalumab. The clinicopathologic features of each patient and rash, and corresponding radiologic findings at the development of the rash and after its treatment, are described. Patients receiving anti-PD-1/PD-L1 mAb may develop immune-related bullous pemphigoid. This may be related to both T-cell and B-cell mediated responses. Referral to dermatology for accurate diagnosis and management is recommended.

Objective To determine etiologies of myonecrosis in oncology patients and to assess interobserver variability in interpreting its MRI features. Materials and Methods Pathology records in our tertiary cancer hospital were searched for proven myonecrosis, and MRIs of affected regions in those patients were identified. MRI reports that suggested myonecrosis also were identified. Each MRI was reviewed independently by two of six readers to assess anatomic site, size, and signal intensities of muscle changes, and presence of the previously reported stipple sign (enhancing foci within a region defined by rim enhancement). The stipple sign was assessed again, weeks after a training session. Cohen kappa and percent agreement were calculated. Medical records were reviewed for contemporaneous causes of myonecrosis. Results MRI reports in 73 patients suggested the diagnosis of myonecrosis; pathologic proof was available in another two. Myonecrosis was frequently associated with radiotherapy (n=34 (45%) patients)); less frequent causes included intraoperative immobilization, trauma, therapeutic embolization, ablation therapy, exercise, and diabetes. Myonecrosis usually involved lower extremity, pelvis, and upper extremity; mean size was 13.0 cm. Stipple sign was observed in 55–95% of patients at first assessment (k=0.09–0.42; 60–80% agreement) and 55–100% at second (k=0.0–0.58; 72–90% agreement). Enhancement surrounded myonecrosis in 55–100% patients (k=0.03 – 0.32; 58–70% agreement). Conclusion Myonecrosis in oncology patients usually occurred after radiotherapy, and less commonly after intraoperative immobilization, trauma, therapeutic embolization, ablation therapy, exercise, or diabetes. Although interobserver variability for MRI features of myonecrosis exists (even after focused training), a combination of findings facilitates diagnosis and conservative management.

The use of CT guidance to perform core biopsies of head and neck masses is an effective means of establishing histopathological diagnosis and reduces the need for diagnostic open surgical biopsy and general anaesthesia.

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