Follicular Thyroid Carcinoma Presenting as Massive Skull Metastasis: A Rare Case Report and Literature Review
A 48-year-old female presented with swelling in the frontal region of the skull since 2 years and another swelling in parieto-occipital region since 4 months. Both the swellings over skull have been painless and gradually progressive in size, thus the delay in presentation. No significant past medical history. On examination, swelling in frontal region measured 18 cm in sagital and 13 cm in coronal directions and 7 cm in vertical dimension. The veins over swelling were distended and it was pulsatile in nature, firm in consistency and fixed to skull. The skin over the swelling was stretched but otherwise normal. Left orbit appeared distorted by the swelling but vision was normal []. The second swelling was located in parieto-occipital region right side and measured 3×4 cm pulsatile in nature and firm in consistency []. Incidentally a thyroid swelling was noted involving mainly right lobe around 3×2 cm, firm and not associated with any pressure symptoms []. Patient did not have any neurological deficit or psychological illness. The patient was clinically euthyroid with normal general physical, systemic, and neurological examination. Routine blood tests and thyroid function tests were normal. Ultrasound study of neck revealed 2 × 1.5 cm neoplastic solid nodule in right lobe of thyroid. Rest of the thyroid gland and neck was normal. X-ray of skull showed lytic lesion in frontal and occipital region of skull. Contrast enhanced computed tomography (CT) demonstrated a 13 × 18 cm size expansile osteolytic lesion in the fronto-parietal region on both right and left side of anterior half of skull. The lesion was extending intracranialy and causing compression of the underlying fronto-parietal lobes on both sides. Similar expansile osteolytic lesion of smaller size are seen in the occipital region on both sides largest measuring 4×3 cm on right side. On postcontrast study, these lesions showed significant enhancement suggesting increased vascularity and also areas of necrosis were present at centre []. Fine needle aspiration cytology (FNAC) from thyroid nodule was reported as follicular neoplasm. FNAC from skull swelling obtained was stained with Leishman stain. Smears showed many syncytial sheets of thyroid follicular cells having monotonous enlarged, hyper chromatic nuclei, and microfollicles containing colloid []. Patient was advised total thyroidectomy and radioiodine therapy but was not willing, hence was administered supraphysiological dose of thyroxine. Till date the patient is on follow-up and able to carry out her routine activities.