October 2020*

A 59 year old female with a large ovarian mass

Contributors: 

Andrew Tharp, MD

Resident physician, PGY-2

Department of Pathology and Laboratory Medicine

Indiana University School of Medicine

Sheila E Segura, MD

Assistant Professor, Department of Pathology and Laboratory Medicine

Indiana University School of Medicine

*This case has been peer reviewed

Clinical history: 

This patient is a 59-year-old female who had been experiencing post-menopausal bleeding for one month prior to presentation. Subsequent pelvic CT scan demonstrated a large pelvic mass of heterogenous density, which measured 17.0 cm in greatest dimension. It was unclear whether the mass was arising from the adnexa or posterior-lateral uterus. Radiologic differential included primary ovarian neoplasms, uterine fibroid, or other uterine neoplasm. The patient underwent exploratory laparotomy which revealed a large left ovarian mass.

Gross

The specimen consisted of a 725 g, 18 x 15 x 6 cm red to purple-pink, irregular, markedly ragged ovarian mass with adherent blood clot and possible fallopian tube. The serosa was noted to be purple-pink, glistening, lobulated and markedly disrupted. The mass on sectioning was tan-pink, soft, heterogeneous, focally cystic and hemorrhagic with extensive necrosis (approximately 50%). No normal ovarian stroma was identified. Definitive fallopian tube was not appreciated.

Microscopic examination and immunohistochemistry: 

Sections show that the tumor is composed of a homogeneous population of small- to medium-sized, round primitive cells that grow in sheets, cords, nests and focally cystic areas with extensive necrosis and numerous rosettes with central lumen. The cells display high nuclear-to-cytoplasmic ratios and brisk mitotic activity. Immunohistochemical stains show that the tumor was positive for CK AE/AE3 (focal), EMA (rare) and NSE (focal), while negative for WT1, synaptophysin, chromogranin, CD56, S100, PAX8, neurofilament, inhibin, calretinin, CD99, alpha-fetoprotein, TTF-1 and GFAP. The combined morphologic findings and immunoprofile are consistent with Central-type Primitive neuroectodermal tumor (cPNET).

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Fig. 1: CT image demonstrating a large heterogenous pelvic mass, approximately 17.0 cm by greatest dimension.

 Fig. 1              

Fig. 2: Low power view shows that the tumor is composed of a homogeneous population of cells that grow in sheets, cords, and nests.

 Fig. 2

Fig. 3: High power view shows that the tumor is composed of small- to medium-sized round primitive cells which display high nuclear-to-cytoplasmic ratios and numerous rosettes with central lumens.    

 Fig. 3

Fig.4:  Focal positivity for Neuron Specific Enolase (NSE) 

Fig.  4

Fig. 5: Focal positivity for AE1/AE3

 Fig. 5

Fig. 6: Negative CD99

Fig. 6

October 2020 Final Diagnosis and Discussion