Highly differentiated follicular carcinoma of the ovary with omental and peritoneal spread in a 22-year-old girl; A diagnostic and counseling challenge.

INTRODUCTION AND IMPORTANCE

Highly differentiated follicular carcinoma of the ovary (HDFCO) is a rare type of thyroid carcinoma originating from struma ovarii, consisting of benign-appearing thyroid follicles spread outside the ovarian tissue.

CASE PRESENTATION

We present a 22-year-old girl who underwent left salpingo-oophorectomy, omental, and peritoneal biopsies for a complex left ovarian mass. Microscopic examination and Immunohistochemical staining led to the diagnosis of HDFCO with tumor deposits affecting the omental and peritoneal biopsies. The patient was counseled about the nature of her disease and the recommended treatment. Thyroidectomy was performed later, revealing a normal thyroid gland. The patient received an ablative dose of radioactive iodine (150 mci) and a suppressive dose of levothyroxine. This is one of the youngest reported patients ever.

CLINICAL DISCUSSION

To our knowledge, the patient presented in this case report is one of the youngest patients ever reported in the literature. In the recent WHO Classification of Female Genital Tumors, the term highly differentiated follicular carcinoma arising from struma ovarii (HDFCO) was introduced, to emphasize its low-grade malignant behavior. Due to its rare incidence, there is no standard treatment strategy, but a plan based on surgical intervention is suggested.

CONCLUSION

Malignant struma ovarii should be put in the differential diagnosis in young patients with suspicious ovarian masses. Adequate patient counseling remains a cornerstone in the journey of management.