Complex Regional Pain Syndrome With Central and Peripheral Nervous System Involvement in a Patient With Metastatic Lung Cancer.

Complex regional pain syndrome (CRPS) is a chronic pain disorder characterized by sensory, motor, autonomic, and trophic disturbances, often following trauma, surgery, or neurologic injury. We present a diagnostically complex case with overlapping features of both type I and type II CRPS in a 64-year-old man with metastatic lung adenocarcinoma involving the central nervous system (CNS). The patient developed neuropathic pain, weakness, and edema in the left upper and lower extremities following trauma, radiation, and cervical and lumbosacral radiculopathies. Although his presentation met the Budapest diagnostic criteria for CRPS, diagnostic clarity was complicated by concurrent central (thalamic metastases) and peripheral (radiculopathy) nervous system pathology. Multimodal treatment, including physical therapy for desensitization and mobility, neuropathic medications such as gabapentin and duloxetine, sympathetic nerve blocks, and psychological support, was initiated and resulted in partial symptomatic improvement. This case highlights the importance of early recognition and a multidisciplinary approach in CRPS, particularly in patients with overlapping central and peripheral neurologic disease. Increased awareness of atypical presentations in oncology patients is essential to prevent diagnostic delays and to guide appropriate, individualized management.