SPONTANEOUS REGRESSION OF SCLC WITH CONCURRENT ACID-FAST BACTERIUM INFECTION: A RARE CASE REPORT

Abstract

SESSION TITLE: Lung Cancer 3 SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: 10/09/2018 01:15 PM - 02:15 PM INTRODUCTION: Spontaneous remission (SR) is the phenomenon of cancer remission without medical treatment and is exceedingly rare for small cell lung carcinoma (SCLC). A few mechanisms explaining SR have been proposed: humoral mediated destruction, surgical trauma, and localized destruction. Here we present a case of SCLC spontaneous remission possibly due to activation of cell-mediated immunity attack on acid fast bacilli. CASE PRESENTATION: We present a 63 year old woman with a 80 pack year smoking history who underwent screening CT that showed a 1 cm nodule in the right upper lobe. Follow up PET/CT confirmed a 16 mm nodule. CT-guided biopsy showed a poorly differentiated carcinoma of small cells with neuroendocrine features, and she was diagnosed with SCLC stage Ia, cT1N0M0. MRI brain was negative for metastasis.Seven weeks later a right upper lobectomy was performed. The surgical pathology was negative for malignancy after reviewing 16 sections. It showed necrotizing granulomatous inflammation containing numerous acid fast organisms presumed to be Mycobacterium tuberculosis and she was started on RIPE therapy. Since the specimen had been placed in formalin, cultures were not obtainable. IGRA testing was negative. Follow up imaging at three months was negative for recurrence. DISCUSSION: A small handful of cases of SCLC spontaneous remission exist in literature (1). Seven cases were associated with antineuronal antibodies. Five cases had no suspected cause other than biopsy or surgery related trauma, that some hypothesize disrupted the cancer’s blood supply or architecture. In our case, a robust immune response against acid fast bacilli, especially when combined with needle biopsy micro-trauma, may induce spontaneous remission.Mycobacteria have shown some relationship with pulmonary malignancy: both cause fevers, dyspnea, hemoptysis, night sweats, and weight loss; both frequently appear as cavitary masses; and they are often misdiagnosed as the other. Usually chronic tuberculosis inflammation and scarring is thought to be a risk factor for developing pulmonary carcinoma, however this case suggests an acute infection may be protective. There are two explanations for this suggestion. First, Mycobacteria enhances a localized cell-mediated response--the same type of response previously shown to destroy SCLC (2). Second, Mycobacterium induces interferon release that promotes HLA-I expression on SCLC cells. The cells then present tumor specific antigen that renders them visible and vulnerable to cell-mediated immunity. Interestingly, clinical trials using Mycobacterium vaccae as an immunotherapeutic agent against SCLC showed some preliminary results (3). The act of biopsy likely facilitated this proposed immunological response resulting in spontaneous remission. CONCLUSIONS: Mycobacterial infection in conjunction with biopsy related trauma may be associated with spontaneous regression of SCLC. Reference #1: Horino T, Takao T, Yamamoto M, Geshi T, Hashimoto K. Spontaneous remission of small cell lung cancer: A case report and review in the literature. Lung Cancer. 2006;53(2):249-252. Reference #2: Traversari C, Meazza R, Coppolecchia M, Basso S, Verrecchia A, van der Bruggen P, Ardizzoni A, Gaggero A, Ferrini S. IFN-gamma gene transfer restores HLA-class I expression and MAGE-3 antigen presentation to CTL in HLA-deficient small cell lung cancer. Gene Therapy. 1997;4(10):1029-35. Reference #3: Assersohn L, Souberbielle BE, O'Brien ME, Archer CD, Mendes R, Bass R, Bromelow KV, Palmer RD, Bouilloux E, Kennard DA, Smith IE. A randomized pilot study of SRL172 (Mycobacterium vaccae) in patients with small cell lung cancer (SCLC) treated with chemotherapy. Clinical oncology. 2002;14(1):23-27. DISCLOSURES: No relevant relationships by William Hatch, source=Web Response No relevant relationships by Rajeev Narang, source=Web Response no disclosure on file for Gerard Voorhees