Discussion (cont): In this case, the identification of homozygous paternal alleles (two distinct paternal alleles, indicated by red asterisks) at three STR loci (lower right panel) confirms the genetic origin of the choriocarcinoma from a homozygous complete mole.

Discussion (cont): Short tandem repeat (STR) genotyping is a powerful tool for distinguishing gestational choriocarcinoma from nongestational tumors with trophoblastic differentiation and for determining whether the antecedent pregnancy was molar or non-molar in origin.

Discussion (cont): While clinical and pathological features may sometimes suffice, choriocarcinoma arising outside the uterus, especially in a young woman, poses a significant diagnostic challenge.

Discussion: Determining the histogenetic origin of an extrauterine choriocarcinoma - gestational, germ cell, or somatic - is critical, as each carries distinct prognostic and therapeutic implications

Diagnosis: Gestational choriocarcinoma arising from ectopic homozygous complete mole.

Discussion (cont): Coupled with the absence of disease elsewhere clinically, the presence of a large unilateral tumour is in favour of a primary ovarian tumour.

Diagnosis: Microscopy indicated a diagnosis of mucinous borderline ovarian tumour of intestinal type.

Discussion: The presence of intestinal-type mucinous epithelium with atypical features but no evidence of invasion indicated a mucinous borderline tumour.

Revised diagnosis: Complex sclerosing lesion/sclerosing papilloma

Secondary review: Appearance is of a sclerosing papillary lesion, Note presence of myoepithelial cells at periphery of distorted nests, Note heterogeneity of epithelial cells within the proliferation (variable nuclei, intranuclear inclusions, nuclear grooves etc.)

Outside hospital work-up: Diagnosis of IDC rendered, breast biomarkers performed, ER/PR was positive (50% variable); HER 2 negative

Cemento-ossifying fibromas are considered odontogenic neoplasms and only occur in the tooth-bearing areas of the jaws according to the current WHO classification. Differential diagnosis of extragnathic lesions include this benign lesion and will be discussed during the course.