SESSION TITLE: Cancer Student/Resident Case Report Posters I
SESSION TYPE: Medical Student/Resident Case Report
PRESENTED ON: Tuesday, October 29, 2013 at 01:30 PM - 02:30 PM
INTRODUCTION: Immunostaining is used in the diagnosis and sub-cellular localization of specific types of cancers and can help guide management strategies. We report an interesting case of a PAX8 positive,Thyroid transcription factor 1 ( TTF-1) negative primary lung cancer.
CASE PRESENTATION: An 80 old lady was incidentally found to have a new lung nodule in her pre-operative Chest X-Ray. She was being evaluated for an exploratory laparotomy for a large pelvic mass(figure 1)of recent onset.She had a strong history of cigarette smoking.A Computerized Tomography (CT)scan of the chest revealed a peripherally located nodule in the left upper lobe measuring 1.4cm x1.2cm x 1cm with no mediastinal lymphadenopathy.CT guided biopsy of the lung mass was positive for a poorly differentiated adenocarcinoma. Immunostaining strongly favored metastasis from a mullerian source as PAX8 was diffusely positive(figure 2),Thyroid Transcription Factor -1(TTF-1) was negative and Estrogen Receptor (ER)was focally positive.She had a vaginal hysterectomy for uterine fibroids 40 years ago.Bilateral salpingo oopherectomy with appendectomy was performed.A mucinous cystadenofibroma which was 26 cm in diameter and weighing 3510 grams was found on the right ovary.PAX8 staining was negative.No borderline features or malignant foci were seen in either ovary ,fallopian tube,pelvic washings or in the appendix. No evidence of intraperitoneal disease like ascitis or lymphadenopathy was present either.CA-125 was normal at 19.Positron Emission Tomography(PET) scan did not reveal any other primary focus.The lung nodule was thus determined to be a primary tumor of the lung and she was scheduled to undergo a lobectomy of the left upper lobe.
DISCUSSION: PAX8 is a transcription factor crucial for organogenesis of thyroid gland,renal and mullerian system.It is a sensitive and specific marker for primary ovarian and renal carcinoma. It is negative in normal and benign ovarian issue.All primary lung adenocarcinomas that have been analyzed to date have been negative for PAX8 and approximately 72% have been positive for TTF-1 which is a marker of lung organogenesis.[1,2]The converse,as in our case,is the first documented case in medical literature for a primary lung adenocarcinoma.
CONCLUSIONS: Immunostaining of tissues with malignant histology can serve as a road map to search for a primary malignant tumor in specific tissues, like the ovary in our case especially in the setting of an ovarian mass.In our case,it also helped identify a new, unique primary lung tumor and plan a subsequent appropriate management strategy for the patient.
Reference #1: Tacha.D. Expression of PAX8 in Normal and Neoplastic Tissues - A Comprehensive Immunohistochemical Study. Applied Immunohistochemistry Molecular Morphology.July 2011;19(4):293-299
Reference #2: Tanaka H. Lineage-specific dependency of lung adenocarcinomas on the lung development regulator TTF-1. Cancer Research.2007;67(13):6007-6011
DISCLOSURE: The following authors have nothing to disclose: Kavitha Bagavathy, Hamid Habibi, Shine Raju, John McArdle
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