Unusual liver Involvement by Small Cell Carcinoma Arising in an Ovarian Malignant Mixed Mullerian Tumor

Abstract

Abstract Introduction/Objective Malignant mixed Mullerian tumor (MMMT) is a rare and aggressive tumor with patient survival of fewer than three years. MMMT harbors multilineage differentiation associated with malignant epithelial and stromal components. Awareness and familiarity with these characteristics are essential for patient stratification and clinical management. Methods/Case Report A 64-year-old female presented with refractory lower abdominal pain and bloating. Imaging studies revealed a 14-cm pelvic mass. The patient underwent urgent hysterectomy with salpingo-oophorectomy. She was diagnosed with ovarian MMMT(A) and received chemotherapy. The patient returned 2 months later with new- onset abdominal pain. CT detected numerous liver lesions; a biopsy was performed. Results (if a Case Study enter NA) The liver biopsy revealed metastatic small cell carcinoma (SCC[B], positive for synaptophysin and CD56; Ki67 >90%.). However, no concurrent lesions were identified on imaging. Further testing was attempted to locate the source of the SCC. Re-review of the MMMT with additional tissue sectioning identified sheets of high-grade pleomorphic malignant cells with a high N:C ratio, arranged in rosettes and without mucin. Additional immunohistochemistry labeled this MMMT diffusely with synaptophysin(C), chromogranin, and CD56. Furthermore, microscopic foci of MMMT showed higher grade histomorphology similar to the liver SCC which stained for PAX5(D). These findings illustrate a rare MMMT with a neuroendocrine carcinoma/SCC component which gave rise to liver metastasis. Conclusion This unusual liver SCC in a patient with prior MMMT exemplifies the multipotent malignant potential of MMMT and demonstrates the importance of having a spectrum of differentials and carrying out meticulous histomorphologic and ancillary analyses, especially when there is unusual histomorphology and discordance in clinical course.