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R. El-Maraghi
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P2.01 - Poster Session/ Treatment of Advanced Diseases – NSCLC (ID 207)
- Event: WCLC 2015
- Type: Poster
- Track: Treatment of Advanced Diseases - NSCLC
- Presentations: 1
- Moderators:
- Coordinates: 9/08/2015, 09:30 - 17:00, Exhibit Hall (Hall B+C)
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P2.01-030 - Challenging Diagnosis of Adenocarcinoma of the Lung Confirmed by Molecular Analysis: A Clinical Case (ID 2757)
09:30 - 09:30 | Author(s): R. El-Maraghi
- Abstract
Background:
Lung cancer is the leading cause of cancer related deaths worldwide, with approximately 1.8 million new cases diagnosed in 2012 resulting in an estimated 1.6 million deaths (Torre 2015). The basic tools of diagnosis include the assessment of clinical status (Rivera 2013), imaging to determine the size and location of tumors as well as the presence of metastases (Liam 2015), and tissue biopsies for establishing tumor histology and molecular subtype (Ofiara 2012). Correct characterization of the primary tumor can be particularly challenging when presentation includes confounding elements such as multiple lesions and/or no definite mass at the primary site. The accuracy and timing of molecular testing can play a vital role in compressing the diagnostic window for adenocarcinoma of the lung, allowing for timely treatment and a broader range of therapeutic options.
Methods:
Local research ethics board approval was obtained for this study. A standard diagnostic work up was undertaken, then supplemented by both internal and external pathological review of the available tissue sample, including EGFR and ALK mutation testing to clarify the diagnosis.
Results:
The patient, a 49 year old male smoker, initially presented with nausea, vomiting, weight loss and shortness of breath. Imaging revealed an anterior mediastinal mass with hilar, mediastinal, bilateral neck and left supraclavicular region lymphadenopathy. Ultrasound confirmed bilateral adrenal lesions and a solid lesion in the right testicle, but no definitive lung mass was identified. Presentation characteristics were initially thought to indicate a lymphoma or germ cell tumour, however, additional analysis of tissue from a biopsy of the supraclavicular node was more consistent with a poorly differentiated carcinoma suggestive of lung adenocarcinoma, with positive staining for TTF-1 and EMA and negative staining for CK20, CK45, CK30, melanoma markers and thyroglobulin. Molecular testing for EGFR and ALK mutations was then requested, along with external pathology review. Findings from external review confirmed the aforementioned molecular profile and revealed that the tumour was also negative for CDX2, CK5, P63, PAX8, OCT3/4, SALL4 and synaptophysin expression, suggestive of thymic cancer, a teratoma, a germ cell tumour, or metastases from upper gastrointestinal origin. Molecular testing results identified an EGFR exon 21 point mutation, confirming the diagnosis of primary lung cancer. Treatment with afatinib was considered; however, due to the protracted diagnostic window, the patient was ultimately too debilitated to receive therapy.
Conclusion:
The absence of a definite lung mass and the unusual clinical and molecular presentation of this case made primary tumour site identification very challenging. The differential diagnosis was ultimately achieved through molecular testing. It is now well-established that early (reflexive testing) knowledge of EGFR and ALK mutation status, accomplished through molecular profiling, is essential for the appropriate management of patients with adenocarcinoma of the lung. However, this case also highlights the importance of this type molecular characterization in achieving a timely diagnosis.
