Metastatic micropapillary cervical adenocarcinoma presenting as a cystic neck mass: a diagnostic pitfall that can be mistaken with metastatic papillary thyroid carcinoma

Abstract

Abstract Introduction/Objective Micropapillary endocervical adenocarcinoma is a rare aggressive variant of cervical adenocarcinoma with a high propensity for lymphovascular spread and poor outcomes. A 69-year-old woman presented with bilateral neck masses for 6 months. Imaging showed multiple multilocular cystic lateral neck masses. Fine needle aspiration was non-diagnostic. A core biopsy showed a papillary adenocarcinoma positive for TTF-1, Napsin-A, and PAX-8 immunostains, and negative for thyroglobulin, interpreted as metastatic papillary carcinoma of possible lung or thyroid origin. Further imaging of the head, neck, and thorax did not reveal a clear primary, but there was extensive involvement of the neck and mediastinal lymph nodes. Given the disease distribution and prominent cystic change in the nodal metastases, the patient underwent total thyroidectomy, bilateral neck, and mediastinal dissections for a presumed thyroid primary. No tumor was found in the thyroid gland. On follow-up the patient was noted to have normal serum thyroglobulin and retroperitoneal lymphadenopathy on PET/CT scan, prompting the search for a pelvic source. Additional immunostains performed in existing samples showed strong estrogen and progesterone receptor expression suggesting a gynecologic primary. At reevaluation, it was found that the patient had postmenopausal bleeding for a year. The colposcopy examination was normal, but a pap smear showed adenocarcinoma. An endocervical biopsy confirmed a micropapillary variant of endocervical adenocarcinoma. Methods/Case Report case report Results (if a Case Study enter NA) NA Conclusion Micropapillary carcinomas occur at multiple sites and are associated with the prominent lymphovascular spread and poor outcomes. The association of prominent neck and mediastinal lymphadenopathy, papillary architecture, cystic metastases, and coexpression of TTF-1, Napsin-A, and PAX-8 led to an erroneous presumption of a thyroid primary. This case highlights how overlapping immunomorphological features between thyroid and gynecologic tumors with papillary architecture, anchoring and confirmation biases, and suboptimal anamnesis can lead to an erroneous diagnosis.