RGUHS Nat. J. Pub. Heal. Sci Vol: 14 Issue: 2 eISSN: pISSN
Sadashiv patil1, S M Patil2, Medide Veerendra3
1,2Professor of Medicine,
3Post-graduate,
Department of Surgery, KBN Instiute of Medical Sciences, Kalaburagi.
Corresponding author
Dr. Sadashiv Patil, Professor of Surgery, KBN Hospital, Main Road kalaburagi, Karnataka.
Abstract
Follicular thyroid carcinoma is the second most common thyroid cancer after papillary carcinoma, but it is ranked first in producing distant metastasis among thyroid carcinomas. It accounts for 20% of all thyroid malignancies and is most often seen in patients over 40 years of age. There have been less than 30 reported cases of cutaneous metastases from follicular thyroid carcinoma in the literature. Majority of them have affected the head and neck region. We present a 60-year old lady with a swelling in the right fronto-parietal region since 9 months . FNAC revealed metastatic follicular carcinoma. Past history revealed patient undergoing total thyroidectomy one year back and was prescribed thyroxine 100mcg, which she had discontinued after one month. Thyroid function test revealed hypothyroidism. Metastatic tumors are TSH dependent and strict TSH suppression is mandatory. Patient was treated with radioactive iodine at a dose of 400 mCi.
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Introduction
Thyroid carcinoma is the most common endocrine malignancy (90% of all endocrine cancers)1. Risk factors include ionizing radiation, presence of thyroid adenoma and multi-nodular goitre. The variants of thyroid carcinoma are Papillary carcinoma (60%), Follicular carcinoma (20%), and Anaplastic carcinoma (10%)2. Thyroid carcinomas are derived from follicular epithelial cells. Follicular carcinoma is known to produce distant metastases, and the common sites are bones, lungs, and central nervous system1. There have been fewer than 30 reports of cutaneous metastases in the literature, and majority of them are to the scalp.
Case report
A 60-year old lady presented in the OPD with a history of a swelling on the right side of the forehead since 9 months. There was no history of pain in the swelling. Swelling began as a small swelling and gradually increased in size. There was no history of trauma. She was receiving amlodipine 5 mg once a day for hypertension.
Past history revealed that she underwent total thyroidectomy 1 year ago. Histopathological report had revealed Follicular variant of papillary carcinoma of thyroid. Patient had been advised Eltroxin 100mcg postoperatively. The patient had stopped taking Eltroxin after 1 month following surgery.
On examination, there was a well-defined, softto-firm, swelling in right frontoparietal region measuring 10X15 cms (Fig.1). There was loss of hair over swelling. Skin was not adherent to the underlying swelling. The swelling was not freely mobile.
Investigation
X-ray skull showed presence of a soft tissue swelling without any bony erosion (Fig.2). Ultrasonogram of the swelling showed presence of iso-to-hypoechoic soft tissue mass measuring 8 x7 cms over right fronto-parietal region of the scalp with underlying erosion of the skull vault. Doppler flow shows signals in the lesion, and no calcification seen. Thyroid function study showed T3 1.23 ng/ml, T4 4.82 mcg/dl and TSH 1.37 milliu/ml. Fine needle aspiration cytology of swelling revealed metastatic follicular carcinoma. Patient received with radioactive iodine(I131) at a dose of 400 mCi.
Discussion
Follicular thyroid carcinomas (FTC) often spread to bones and lung5. The occurrence of cutaneous metastases is a rare event, and it predominantly affects the skin of head and neck4.Thyroid secondaries affect the-skull and cause osteolytic lesion as in the present case The secondaries are cutaneous. Differentiated thyroid cancers are TSH dependent. It is a standard practice to prescribe 0.1 to 0.2 mg of thyroxin for all differentiated thyroid cancers to suppress endogenous TSH production. TSH levels less than 0.1 milliunits/l indicates an inadequate dose of thyroxine or that the patient is non compliant2.
Metastatic lesions are hard in consistency, but in our case the swelling was soft-to-firm in consistency. Metastatic thyroid carcinoma usually produces osteolytic bony lesions.
Patient with distant metastases requiring repeated admission of radioactive iodine for scanning and therapy should be given T3 40 to 60 mcg daily as it is short acting. TSH secretion and thyroid avidity for iodine recover quickly, so that radio iodine given in days, instead of weeks of hypothyroidism with T4.
Conclusion
Post-operative thyroxine suppresses the TSH secretion. Differentiated thyroid carcinomas are TSH dependent.
Supporting File
References
- Rahman GA, et al Unusual cutaneous metastatic FTC Jour Surg Technique and case report 2010; 2:1.
- Bailey and Love’s Short Practice of Surgery 25th edn.
- Cupiste K , et al.Multiple giant scalp metastases of a follicular thyroid carcinoma,World Jour Surg Oncol 2008: 6: 82.
- Quinn TR, et al Cutaneous metastases of follicular thyroid carcinoma: a report of four cases and a review of the literature. Am J Dermatopathol 2005, 27: 306-312.
- Durante C et al Long-term outcome of 444 patients with distant metastases from papillary and follicular thyroid carcinoma: benefits and limits of radioiodine therapy J Clin Endocrinol Metab. 2006, 91: 2892-2896.