Subgroup: Volume 9, Issue 3
Type: Case Report
Start Page: 161
End Page: 163
- F Safarpor Department of Surgery,Guilan University of Medical Sciences, Guilan, iran
- MH HedayatiOmami Guilan Endocrine and Metabolism Research Center,Department of Internal Medicine, Guilan, iran,
- F Mohammadi Guilan Endocrine and Metabolism Research Center,Department of Internal Medicine, Guilan, iran,
- S Hoda Department of Pathology, Guilan University of Medical Sciences, Guilan,41448,Iran, Guilan, Iran
- D Safarpor Department of SurgeryGuilan University of Medical Sciences, Guilan, Iran,
City, Province: , Guilan
The incidence of tuberculosis is high and extrapulmonary tuberculosis is seen more frequently, the thyroid tuberculosis is rare. Thyroid tuberculosis is presented as thyroid nodule, thyroiditis or abscess formation. This condition should therefore be recognized whenever goiter is being treated, because it has an entirely different treatment. The aim of this report is to present thyroid tuberculosis in order to gain a better understanding of its clinical characteristic, diagnosis and treatment we present 9 cases of thyroid tuberculosis since 1995-2006 from north of Iran. They comprised 5 patients with thyroiditis, 2 cases with abscess formation and 2 with thyroid nodules. All patients were diagnosed using Fine Needle Aspiration (FNA) and treated by repeated surgery and anti-tuberculosis drugs. It is concluded that tuberculosis of thyroid should be kept in mind while treating diseases of the thyroid such as thyroid nodule, thyroiditis, thyrotoxicosis especially in communities with high prevalence of tuberculosis. The diagnosis of thyroid tuberculosis is facilitated by FNA and its treatment is achieved by simple surgery as well as anti-tuberculosis therapy.
Keywords: Thyroid; Tuberculosis; Southern Iran
The tuberculous involvement of thyroid gland is so rare that according to Rokitansky (1859) it never occurs.1 Clute and Smith (1927) reported one case of thyroid tuberculosis in approximately 1200 thyroidectomies1 and Levitt (1959) recorded only 2 cases among 2114 operations on thyroid gland.1 Rankin and Graham found thyroid gland tuberculosis in 21of 20758 (0.1%) cases of thyroid gland excision.2
The ability of the thyroid gland to resist infection is well known but reason for this entity remains unclear. Several hypotheses made to explain this phenomenon included the presence of colloid material possessing bactericidal action, extremely high blood flow and an excess of iodine which enhanced destruction of tubercle bacilli by increasing physiologic activity of phagocytes in hyperthyroidism. Tuberculosis infection spread to the thyroid through lymphatic and lymphogenous route or directly from adjacent organs. The clinical diagnosis of thyroid tuberculosis is rarely investigated unless there is a sinus in the gland with chronic discharge. A past history of tuberculosis concomitant with cervical lymphadenopathy and the sites of tuberculous involvement might lead to the correct clinical diagnosis. The principal methods for establishing diagnosis of thyroid tuberculosis are FNA with subsequent bacteriological investigation. Furthermore, for verification of diagnosis, ultrasonography, in conjunction with computerized tomography and the latest and sophisticated diagnostic methods of tuberculosis may be necessary. Thyroid tuberculosis should be differentiated from the main diseases of thyroid, particularly thyroid cancer in order to avoid unnecessary thyroid surgery.3 Anti- tuberculosis therapy of the thyroid gland along with surgical removal of affected parts are the most common methods for treatment of thyroid tuberculosis.3,4
The invasion by Mycobacterium tuberculosis of thyroid gland is rare even in the case of patients with pulmonary tuberculosis, compared to the invasion of other organs. Tuberculosis of the thyroid gland assumes various forms such as diffuse goiter, soft or hard nodule, painful and swollen thyroiditis, or an acute or cold abscess.5
Our study comprised 5 patients presented as thyroiditis, 2 with thyroid nodule and 2 with abscess formation. In regard to gender, the incidence in most reports appears to be nearly equal but in our study 6 cases were females with no predilection for any particular age and their ages ranged from 25 to 76 years. Duration of symptoms varied from 3 weeks to 8 months. In 7 patients the main complaint was a swelling in the neck. However, two patients had thyroid nodule with no swollen neck and pain. Weight loss, night sweat, fever and fatigue were the most common symptoms.
Symptoms due to pressure effect including dysphagia, dyspnea and dysphonia, sometimes reported in other studies, did not occur in any of our patients. Disorders of thyroid function were rare and enlargement of regional lymph nodes reported in other study6 was not found in any of our patients. In order to prove or dismiss thyroid tuberculosis, it may be necessary to apply all or most methods used for diagnosis of tuberculosis which ranged from the most simple techniques such as chest x ray and PPD to the sophisticated and rapid serological assays, whereby antibodies to mycobacterium tuberculosis are detected in human serum or plasma.7 FNA is performed in order to detect tuberculosis of the thyroid. Although the incidence of thyroid tuberculosis in Rankin and Graham report was 0.1% but the report of Das et al. study by FNA was o.6%.8 Cytological evaluation of aspirated material showed multinucleated giant cells, histiocytes and lymphocytes which in conjunction with positive Ziehl-Neelsen staining and culture of the aspirated material confirmed the diagnosis of thyroid tuberculosis. Our diagnosis of thyroid tuberculosis in all 9 patients was based on the results of FNA, acid fast staining and culturing.
Our study as well as those of others confirmed the efficacy and cost-effectiveness of this approach for diagnosis of thyroid tuberculosis.6,7 Ultrasonography and computed tomography findings were also helpful in the diagnosis of thyroid tuberculosis as heterogenous hypoechoic mass seen on ultrasonogram and peripheral-enhancing low-density abscess with regional lymphadenopathy demonstrated on CT scan could assist in detecting thyroid tuberculosis.9 Sometimes it is difficult to diagnose thyroid tuberculosis preoperatively or even during surgery and thyroid tuberculosis is diagnosed basically by histological finding during examination of surgically removed thyroid material.10,11 The prerequisite for diagnosis of thyroid tuberculosis described in early 1939 included demonstration of acid fast bacilli (AFB) within thyroid, a necrotic or abscess formation and demonstration of tuberculous focus in other organs. Histological and bacteriological confirmations are adequate and fulfillment of third criterion is not essential. As acid fast bacilli are not always found, multiple coalesced and caseated epitheloid cell granolomas along with giant cells are considered to be diagnostic of tuberculosis infection of thyroid.11 Anti-tuberculosis therapy and surgical removal of affected parts of the thyroid gland are the most common methods of treatment of thyroid tuberculosis. Currently, drainage through repeated puncture in combination with anti-tuberculosis therapy is also considered as other modes of treatment. The tuberculosis infection of thyroid, although a rare entity, should be kept in mind whenever thyroid disorders notably in patients with a history of tuberculosis are investigated. FNA, with direct staining for AFB and culturing of aspirated material for mycobacterium tuberculosis represent the procedures of choice for making appropriate diagnosis. Surgical removal of affected tissue and repeated puncturing for drainage of mass along with anti-tuberculosis therapy would help and prevent the disease.
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- Rankin FW, Graham AS. Tuberculosis of the thyroid gland. Ann Surg 1932;96:625-48.
- Magboo ML, Clark OH. Primary thyroid abscess mimiking carcinoma diagnosed by FNA. West J Med 1990;153:657-9.
- Barnes P, Weatherstone R. Tuberculosis of the thyroid: two cases report. Br J Dis Chest 1979:73:187-91.
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- Khalil EA, E lsidding KE, Elsafi ME, et al. supra sternal-nuch tuberculouse abscess:a report of 3 cases Trans R Soc Trop Med Hyg 2000;94:58-60.
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- Kang BC, Lee-Shim SS, Choi H, Baek Y, Cheon YJ. US and CT finding of tuberculosis of thyroid gland: 3 cases report. Clin Imaging 2000;24(5):283.
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- Tabacu E, Galie N, Galbenu P, Mitrea M. Thyroid tuberculosis: a clinical case. Pneumologia 2000;49(1):41-4.