SESSION TITLE: Miscellaneous Global Case Reports
SESSION TYPE: Global Case Report
PRESENTED ON: Tuesday, October 29, 2013 at 01:30 PM - 02:30 PM
INTRODUCTION: Small cell lung carcinoma (SCLC) comprised 10-15% of lung cancers. Combined SCLC (c-SCLC) is defined by World Health Organisation to be SCLC combined with an additional component (at least 10%) that consists of any of the histologic types of non-small cell carcinoma, usually adenocarcinoma, squamous cell carcinoma or large cell carcinoma but less commonly spindle cell or giant cell carcinoma(1). Previous studies showed that up to 30% of SCLC had such mixed histology at diagnosis. Though clinical characteristics of patients with c-SCLC are similar to SCLC, there was controversy about prognosis in this group of patients. Early studies indicated a worse prognosis as response to chemotherapy was poorer and there is usually a delay in diagnosing the second subtype due to inadequacy in sampling(2). Metastatic behavior of c-SCLC is variable: metastases may be pure SLCL, combined or either of its component tumors. We present a rare case of c-SCLC which re-presented itself as a chest wall mass at the site of previous thoracocentesis.
CASE PRESENTATION: A 37 year old Vietnamese lady presented with non-productive cough for 6 weeks and dyspnoea for 2 weeks duration. Breath sound was decreased over the right lung. Chest X-ray and ultrasound of the chest confirmed a massive effusion. Pleural drain was inserted and fluid analysis showed a lymphocytic exudate, positive for adenocarcinoma (EGFR+). CT of the thorax showed a right hilar mass. Bronchoscopy did not reveal any endobronchial mass, but the superior basal segment of right lower bronchus was completely obstructed by extrinsic compression. Workup for metastases was negative. Gefitinib was started and patient was discharged to continue chemotherapy on an outpatient basis. After 3 months, patient complained of increasing breathlessness and a mass on the right posterior chest wall at the site of previous thoracocentesis. Patient claimed the mass had steadily grew in size since started as a lump a few days after discharge. It was hard, fixed, and slightly tender to touch and about 4x4 cm in size (images of this lesion will be attached). CT thorax revealed interval progression of disease with involvement of the whole right lung with right posterolateral chest wall extension to produce a subcutaneous mass and inferior transphrenic extension into the right liver lobe. Histology from percutaneous biopsy demonstrated that the mass has features of a mixed adenocarcinoma and small cell carcinoma. Patient received cisplatin and etoposide therapy and was planned for subsequent palliative radiotherapy.
DISCUSSION: SCLC is an aggressive type of lung cancer. About 70% of patients present with metastatic disease. Even in patients with limited disease, the median survival is 15 to 20 months. SCLC consists of heterogeneous cell types previously classified into oat cell, intermediate cell type, and combined cell type. In 2004, WHO simplified this classification by dichotomising SCLCs into pure SCLC and combined SCLC. The incidence of c-SCLC is likely underestimated due to sampling inadequacy. We postulate that with the advent of molecularly targeted drugs such as tyrosine kinase inhibitors (TKIs) in adenocarcinoma, the prognosis of certain subgroups of c-SCLC patients i.e SCLC/adenocarcinoma will improve if diagnosed early. The hunt for histology should not stop at one in SCLC. Malignant seeding after diagnostic or therapeutic procedures is a well-known complication in malignant pleural mesothelioma. Little is known of this in malignant epithelial tumours of the lung. With improved survival of lung cancer patients especially those with adenocarcinoma on TKIs and increasing number of indwelling tunnelled pleural catheters being deployed for relief of symptomatic malignant pleural effusion, more attention should be drawn to this potential complication. Will there be a role for prophylactic irradiation of the needle tract as in malignant pleural mesothelioma in the future?
CONCLUSIONS: c-SCLC represents a highly variable subset of lung carcinomas. More studies should be done to explore the true incidence and prognostic markers in this group of patients.
Reference #1: World Health Organization classification of tumours. Pathology and genetics of tumours of the lung, pleura, thymus and heart, IARC Press, Lyon 2004.
Reference #2: Adelstein DJ, Tomashefski JF Jr, Snow NJ, et al. Mixed small cell and non-small cell lung cancer. Chest. 1986;89:699-704.
DISCLOSURE: The following authors have nothing to disclose: Chuen Peng Lee, Teh Adeline, Cheila May Dizon Coliat, Christopher Seet, Kim Hoong Yap, Wee See Yap
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