INTRODUCTION: The pleural is a potential source of metastatic deposits from a myriad of cancers, however such deposits are preceeded by detectable primaries. We present an unusual case of a large pleural effusion with pleural nodules but no clinical evidence of a primary focus by CT and CT/PET scanning. The primary origin of the tumor was discovered after extensive immunohistochemistry was which revealed an ovarian origin and excluded other relevant organ sites Metastatic paillary cancer from the ovary to the pleura is very uncommon in the abscence of subdiaphragmatic peritoneal seeding. This is an index case report.
CASE PRESENTATION: The patient is a 41 yr old Caucasian Female with no past medical history who was referred for shortness of breath and a large right pleural effusion. She had no fever, chills,recent infections, weight loss, cough, or night sweats. She had a recent pelvic exam, ultrasound and a mammogram which were negative. A diagnostic and therapeutic thoracentesis produced 1 L of straw coloured, turbid fluid which was exudative with a protein of 5.1 (serum protein 6.4), LDH 580(serum LDH 450), a normal pH and 43% neutrophils, 40% lymphocytes,and the rest were “other” cells. The cytology revealed revealed numerous lymphocytes with aypical, reactive cells. Epithelial cell markers were negative by immunohistochemistry but macrophage and mesothelial cell markers were very revealed reactive histicytes and mesothelial cells. No malignant cells were identified. The effusion promptly reaccumulated and a VATS with pleural biopsies of visible nodules revealed papillary carcinoma by light microscopy. To clarify cell lineage, immunohistochemistry was performed and revealed reactivity for CK7, estrogen and progesterone receptors, and CA-125 (ovarian markers), with no reactivity for TTF-1,thyroglobulin(thyroid markers), CK20, CK5/6, Calretinin, CEA, BRST2, or Her2. This immunophenotype supports gynaecological papillary serous carcinoma, and excludes the lung, mesothelium, breast and thyroid gland as primaries. A CT of the abdomen and pelvis, a pelvic ultrasound, a total body PET scan, and a thyroid scan did not reveal a primary. She had an exploratory laparotomy where a one centimeter sized mass was found on the peritoneum in the cul de sac, which was removed and found to be carcinoma (special stains to confirm the ovarian origin are pending). A total hysterectomy and salphingo-oophorectomy with no gross abnormalty noted in these organs. A histologic evalution of the removed organs is pending.
DISCUSSIONS: This is a very uncommon presentation for metastatic papillary carcinoma of gynaecological origin presenting as a large pleural effusion. While it is not uncommon for metastasis to the pleural space to occur this is usually associated with a pelvic mass and peritoneal seeding, these were absent in our patient by CT and PET and found only by surgical exploration, which is very intriguing. This case is not truly Meigs' Syndrome which is a benign pleural effision in the setting of a pelvic malignancy.
CONCLUSION: This case illustrates one of the limits of light microscopic evaluation of pleural fluid cells even after large large volume sampling in making the diagnosis of cancer. The immunohistochemical staining, even though time consuming and expensive, was able to confirm the organ of origin and allowed a more focused approach for further diagnosis efforts. The advances in immunohistochemical staining over the last decade are a tribute to modern molecular biology and represents a major leap forward in molecular pathology which come to the aide of clinicians facing enigmatic cases.
DISCLOSURE: Ayorinde Medaiyese, None.