A CASE OF SCLEROTIC BONE METASTASIS AS A PRESENTATION OF LUNG ADENOCARCINOMA

Abstract

TOPIC: Lung Cancer TYPE: Medical Student/Resident Case Reports INTRODUCTION: Lung Cancers are the third most common cause of bone metastasis. It occurs in 30-40% of patients during the course of illness. Osteolytic lesions are the most common histopathologic form of bone metastasis of lung origin. Although sclerotic bone changes have been reported in patients with NSCLC undergoing treatment with TKI (Tyrosine Kinase Inhibitors), Lung adenocarcinoma rarely presents initially with sclerotic bone metastasis. Here we have a patient with no prior history of lung cancer or chemotherapy who presented sclerotic bone metastasis originating from a Lung adenocarcinoma. CASE PRESENTATION: A 69-year-old male with no history of smoking presented to the ED with a one-month history of severe progressive lower back pain that radiates to bilateral upper thighs. He also had left shoulder pain that affected his daily activities and sleep. His condition was associated with 15 Ib weight loss over the last 3 months prior to presentation. The patient did not report any respiratory symptoms but he reported chronic difficulty urination, hesitancy, and frequency. A CT lumbar spine was remarkable for diffuse sclerosis of the L4 vertebral body. MRI confirmed that the L4 vertebral body has been replaced by a sclerotic metastatic lesion, as well as a 2nd metastasis present in the left side of L1. Given the dense sclerosis, Prostate Cancer metastasis was highly suggested. A rectal exam revealed no suspicion for malignancy and PSA was normal at a value of 1.020 ng/ml. Bone scan showed intense activity of L4, left side of L1, the proximal left humerus, and right scapula. A CT chest showed a 2.5 cm x 1.5 cm x 1.8 cm mass in the superior segment of the LLL. CT-guided bone biopsy was performed, which showed a metastatic adenocarcinoma of primary lung origin. Lab workup showed normal CBC, Calcium level, kidney and liver functions. The patient was stable so he was referred to Hematology/Oncology clinic for further management. DISCUSSION: Bone is the preferred site for metastasis for some of the most common malignancies, including Prostate, Breast, and Lung cancers. Bone metastasis is classified as osteolytic, osteoblastic, or mixed, according to the primary mechanism of interference with normal bone remodeling and the radiographic appearance. Osteolytic bone lesions are the typical picture for bone metastasis originating from non-small cell lung cancer. Also, It had been noticed that patients with osteolytic metastasis with EGFR mutation would have an osteoblastic reaction during treatment EGFR-TKI which may indicate a good treatment response. Only very few cases have been reported in the literature that presented initially with osteoblastic bone metastasis originating from non-small cell lung cancer, as what we have here in this patient. The exact mechanism of osteoblastic bone metastasis in NSCLC is not fully clear yet. CONCLUSIONS: Lung adenocarcinoma may present with sclerotic bone metastasis REFERENCE #1: Mutational profiling of bone metastases from lung adenocarcinoma: results of a prospective study (POUMOS-TEC) 2014 Oct 1Cyrille B Confavreux, a,1,2 Nicolas Girard,3 Jean-Baptiste Pialat,1,4 Pierre-Paul Bringuier,5,6 Mojgan Devouassoux-Shisheboran,6,7 Jean-Charles Rousseau,1 Sylvie Isaac,8 Françoise Thivolet-Bejui,9 Philippe Clezardin,1 and Marie Brevet1, REFERENCE #2: Osteoblastic Bone Lesions Developing During Treatment with Erlotinib Indicate Major Response in Patients with Non-small Cell Lung Cancer: A Brief Report April 1010 Joline S.W.LindMBBS, MAPieter E.PostmusMD, PhDEgbert F.SmitMD, PhD REFERENCE #3: David Roodman G, Silbermann R. Mechanisms of osteolytic and osteoblastic skeletal lesions. Bonekey Rep. 2015;4:753. Published 2015 Oct 28. doi:10.1038/bonekey.2015.122 DISCLOSURES: No relevant relationships by Ibimina Dagogo-Jack, source=Web Response No relevant relationships by Maged Ghaly, source=Web Response No relevant relationships by Sukhmanjot Kaur, source=Web Response