Hypothyroidism masquerading as ovarian malignancy.

Abstract

A 9 years and 1-month-old girl was referred to us for evaluation of precocious puberty because of suspected ovarian malignancy. She had presented with progressive enlargement of bilateral breasts and per vaginal bleeding for last three months along with evidence of large cystic ovaries and raised cancer antigen 125 (CA-125) level of 54 IU/mL (normal <35 IU/mL). There was no family history of thyroid disorders or precocious puberty. Clinical evaluation showed short stature (height-117 cm, < 5th percentile), normal weight (26 kg, 75th percentile), Tanner stage 3 breast development without axillary or pubic hair growth. She had pallor and mild facial puffiness, but no goitre. Radiological evaluation showed a bone age of 6 years. Ultrasonography showed presence of a pubertal uterus and large multicystic ovaries (Fig. 1a,b). Biochemical evaluation showed pre pubertal luteinizing hormone (LH) level (0.12 mIU/mL, normal: 0.02–0.6 mIU/mL) elevated follicle-stimulating hormone (FSH) level (7.31 mIU/mL, normal: 0.5–4.5 mIU/mL) and elevated prolactin level (43.37 ng/mL: normal 5–25 ng/mL). Thyroid function tests showed a low serum free triiodothyronine (FT3) of 1.04 pg/mL (normal range: 2.02–4.43 pg/mL), low serum free thyroxine (FT4) of 0.45 ng/dL (normal range: 0.93–1.71 ng/dL), coupled with high thyroid-stimulating hormone (TSH) level of >500 mIU/mL (normal: 0.35–5.5 mIU/mL). Anti-thyroid peroxidise antibody (305.2 IU/mL, normal 0–35 IU/mL) was positive. (a) Ultrasound scan photograph showing a pubertal uterus (8.2 × 2.2 × 3.7 cm) with 5-mm endometrial echogenicity. (b) Presence of large multicystic ovaries (right ovary – 6.5 × 3.5 cm and left ovary – 8.3 × 3.4 cm with largest cyst in left ovary measuring around 4.2 cm). (c) Follow-up USG showing considerable decrease in ovarian cyst size (left ovary – 3.1 × 2.1 cm). (d) Similar decrease in right ovary size (2.7 × 1.8 cm). The presence of enlarged cystic ovaries with sexual precocity and raised tumour marker level points to the possibility of oestrogen secreting ovarian tumour. However presence of gross hypothyroidism, a delayed bone age, FSH predominant response and absence of pubic and axillary hair pointed towards the diagnosis of Van Wyk–Grumbach syndrome. She was instituted replacement dose of levothyroxine. After 6 months of therapy, there was marked clinical improvement and considerable resolution in cyst size (Fig. 1c,d). Usually untreated juvenile hypothyroidism presents with delayed puberty and growth retardation. However, in rare circumstances it can lead to isosexual precocity in children. Van Wyk–Grumbach syndrome represents one of the puzzling manifestations of hypothyroidism. Girls with this syndrome have breast development, follicular cysts and menstruation in the absence of pubic or axillary hair, which depends on adrenal androgens.1, 2 As compared with girls, boys have macroorchidism without significant virilisation, and testicular histology shows a predominance of tubular elements without elevated Leydig's cell number, consistent with an FSH-mediated response.3 The exact cause is unknown, but one possible explanation is cross reactivity of the structurally similar FSH and TSH glycoproteins, which share a common alpha subunit and stimulation of FSH receptor by action of elevated TSH resulting in an FSH/oestradiol-predominant response.1-3 Excessive thyrotropin-releasing hormone causes hyperprolactinaemia, which in turn slows gonadotropin-releasing hormone (GnRH) pulse frequency.2 Slow GnRH pulses preferentially lead to suppression of LH and production of FSH.4 Tumour markers such as CA 125 and alpha fetoprotein (usually associated with ovarian malignancy) may be raised in this condition and normalize with treatment.5 Hence, hypothyroidism can rarely simulate clinical presentation of ovarian malignancy.