Author of

• 13580

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  P1.04 - Poster Session/ Biology, Pathology, and Molecular Testing (ID 233)

  • Event: WCLC 2015
  • Type: Poster
  • Track: Biology, Pathology, and Molecular Testing
  • Presentations: 1
  • Moderators:
  • Coordinates: 9/07/2015, 09:30 - 17:00, Exhibit Hall (Hall B+C)

  • 13613

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    P1.04-033 - Case of a Patient Who Underwent Right Middle Lobectomy of Lung Adenocarcinoma with Histological Characteristics Similar to Papillary Adenoma (ID 415)

    09:30 - 09:30  |  Author(s): M. Takahashi
    • Abstract

    Background:
    Pulmonary papillary adenoma is a rare benign tumor of the lung, characterized by a histological appearance in which low-grade cuboid or single columnar cells proliferate, centering on the fibrovascular interstitium. Since diagnosis is made morphologically, genetic analysis is not used for its diagnosis in common practice.
    
    Methods:
    [Case presentation] A 60-year-old woman with no history of smoking or asbestos exposure was referred to our hospital with lung cancer suspected due to an abnormal shadow detected on a plain chest radiograph for screening. A mass lesion 3.5 cm in diameter was detected in the right middle lobe on chest computed tomography (CT). Although positron emission tomography (PET)/CT revealed fluorodeoxyglucose accumulation in the mass (SUV max 3.4), there was no other clear accumulation and there were no findings indicating lymph node metastasis or distant metastasis on enhanced CT and magnetic resonance imaging (MRI) scans. Therefore, the clinical stage was estimated as cT2aN0M0, stage IB. As a treatment strategy, we decided to use surgical biopsy because a definitive diagnosis could not be made from bronchoscopy. Thoracoscopy showed no apparent pleural dissemination or pleural effusion. Since the tumor in the middle lobe was difficult to resect, we resected the middle lobe and submitted it for intraoperative pathological examination. As a result, it was diagnosed as pulmonary papillary adenoma. Consequently, in surgery, systematic lymph node excision was not performed and samples were obtained from lymph nodes #11s and #11i. The permanent preparation showed the appearance of cuboid and low columnar-shaped cells proliferating on the fibrovascular interstitium, which was consistent with papillary adenoma. However, it also indicated a marginal region of lepidic pattern with focal low papillary projection. In immunohistological examination, both the marginal region and the body of tumor were stained with epidermal growth factor receptor (EGFR) mutation specific antibodies. Furthermore, genetic mutation was found in EGFR genetic analysis. Thus, this patient was diagnosed with invasive adenocarcinoma in papillary pattern predominant. The final pathological stage was estimated as T2aN0M0. However, adjuvant postoperative treatment was not performed. The patient was followed up in the outpatient department, and no recurrence has been observed eight months.
    
    Results:
    [Discussion] Pulmonary papillary adenoma is commonly diagnosed based on the histological forms and genetic examination is not usually used. Thus, we cannot deny the possibility that lesions with gene mutations have been present in the patients diagnosed with papillary adenoma in the past. In addition, in patients with a large primary tumor with a morphologically low grade, it is difficult to judge whether postoperative treatment should be provided and it is considered necessary to judge it by taking the clinical course into account.
    
    Conclusion:
    Pulmonary papillary adenoma is a rare tumor. To obtain the definite diagnosis with the exclusion of malignancy, it has been suggested that complete resection and genetic analysis is necessary .