Anaplastic carcinoma of the ovary is a rare subtype of ovarian cancer. While incompletely understood, these cancers are known to be highly aggressive and typically exhibit a poorer prognosis than other types of ovarian cancer. Anaplastic ovarian carcinomas are often described as a sarcomatous focus within a mural nodule of a larger mucinous borderline ovarian tumor or mucinous ovarian carcinoma [1]. While this is the typical histologic presentation, anaplasia within ovarian carcinomas can be found in the absence of a mural nodule or mucinous histology. Notably, anaplastic carcinoma of the ovary is a distinct entity from anaplastic thyroid cancer, which rarely metastasizes to the ovary [2]. Much of the existing knowledge on anaplastic carcinoma of the ovary in the literature is comprised by case reports and small case series [[3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13]].

Sarcomatous nodules in ovarian mucinous tumors were first described in 1979 by Prat and Scully from the Massachusetts General Hospital, in a case report of 2 patients with these tumors who died of their disease within 1½ years of diagnosis [12]. They reported on these patients concurrently with a series of 7 patients with sarcoma-like nodules, showing prognostic favorability for the tumors that did not meet criteria for true sarcoma classification [13]. They followed up with a report on another 4 patients in 1982, describing a cohort with anaplastic carcinoma foci within solid nodules of ovarian mucinous tumors [14]. They cautioned that these may easily be confused with sarcomatous foci in nodules or with sarcoma-like nodules, but emphasized that sarcoma and carcinoma must be distinguished from sarcoma-like nodules due to prognostic significance [14]. In 2002, Bagué, Rodríguez, and Prat reported on 10 mucinous ovarian tumors with sarcoma-like nodules, again showing that these have a generally favorable prognosis [15]. Provenza et al., under the leadership of Prat, reported on a larger series in 2008 of 34 patients with anaplastic carcinoma of the ovary, redemonstrating the generally poor prognosis of these tumors; however, with the caveat that stage IA tumors had a generally good prognosis, suggesting the presence of anaplastic carcinoma in unruptured mucinous tumors may not have prognostic significance [16].

Moving forward to the molecular age, Chapel et al. published a series in 2021 describing the Dana Farber Cancer Institute/Brigham and Women's Hospital's experience with mucinous ovarian tumors with mural nodules. They reported on their molecular analysis of 13 patients, 10 with sarcomatous/anaplastic carcinomatous nodules and 3 with sarcoma-like nodules, which are known to be more favorable, as discussed above [1]. They showed evidence of clonality between mucinous ovarian tumors and their respective mural nodules, as well as recurrent alterations in TP53, KRAS, and CDKN2A [1]. They found no clear molecular driver of mural nodule development or differences between sarcoma-like nodules and nodules with true sarcoma or anaplastic carcinoma [1].

In the present work, we report on our institutional experience at a tertiary cancer center with anaplastic ovarian carcinoma over the course of one decade (2013−2023). We focus on clinical course, prognosis, and choice of systemic therapy, with special attention to molecular underpinnings.