542 - More Than Just Back Pain: A Case of Metastatic Small Cell Lung Carcinoma

Case Diagnosis: Undiagnosed metastatic small cell lung carcinoma resulting in lower back pain

Case Description: An 87 year-old community-dwelling male with a history of gout presented with burning, radiating low back pain without inciting trauma progressing gradually throughout 3 years with exacerbation over the last 2 months. Prior sacroiliac (SI) joint corticosteroid (CSI) injection under ultrasound guidance helped temporarily. Physical exam revealed sacral sulcus tenderness without radicular or dural tension signs. Functional status evaluation was notable for decreased ambulatory distance secondary to pain necessitating a walker. Imaging revealed SI joint sclerosis, degenerative lumbar disc disease, and vascular calcifications. A month later, patient reported daytime relief with NSAIDs, but nighttime awakenings due to pain caused him to sleep upright on recliner. Repeat SI CSI injection provided minimal relief. Burning pain progressed down bilateral legs and feet, associated with chills, night sweats, and hot flashes.

Discussions: A multidisciplinary approach ultimately led to PET Scan revealing avid tumor involvement in the lungs and metastatic disease to liver, lymph nodes, and osseous structures. After a round of radiation and chemotherapy complicated by steep desaturations, he is now receiving hospice at home with cancer rehabilitation and palliative care management. There is extensive literature documenting the importance of vascular calcifications in relation to malignancy. While the absence of constitutional symptoms places malignancy low on the differential, a detailed review of systems must be considered for this multifactorial condition before referral to interventional pain management.

Conclusions: In the realm of physical medicine and rehabilitation, acute on chronic lower back pain is seen as a musculoskeletal issue. Addressing back pain as a primary pain generator may progress functional outcomes temporarily, but secondary clues hidden in clinical examination can be rediscovered in plain film imaging. Non-specific findings like vascular calcifications should raise suspicion for malignancy and lead to a more comprehensive and timely work-up.