Indian Journal of Pathology and Microbiology

: 2008  |  Volume : 51  |  Issue : 4  |  Page : 521--522

Adenolipoma of the thyroid gland

Anshu Gupta1, SK Mathur1, Charu Batra1, Anjali Gupta2,  
1 Department of Pathology, Institute of Human Behavior and Allied Sciences, Delhi, India
2 Department of Obstetrics and Gynecology, Pt. B.D.S. PGIMS, Rohtak, India

Correspondence Address:
Anshu Gupta
1408/13, Opposite Model School, Civil Road, Rohtak 124 001


Thyrolipoma or adenolipoma of the thyroid gland is defined as a thyroid adenoma containing mature fat tissue. It is a rare encapsulated lesion. A case of a 35-year-old female presenting with swelling in the neck that was diagnosed as adenolipoma is described because of its extreme rarity.

How to cite this article:
Gupta A, Mathur S K, Batra C, Gupta A. Adenolipoma of the thyroid gland.Indian J Pathol Microbiol 2008;51:521-522

How to cite this URL:
Gupta A, Mathur S K, Batra C, Gupta A. Adenolipoma of the thyroid gland. Indian J Pathol Microbiol [serial online] 2008 [cited 2020 Sep 20 ];51:521-522
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Full Text


Adenolipoma of the thyroid gland has been termed adenolipoma, thyrolipoma, and thyroid hamartoma. [1] This tumor is composed of tissue of the thyroid gland and fat in different proportions and is usually encapsulated. [2],[3] These tumors are benign and usually biologically inactive neoplasms of the thyroid gland. [4],[5],[6],[7]

 Case Report

A 35-year-old female presented with a 3-month history of a mass in the neck. On clinical examination, the right lobe of the thyroid was enlarged. The gland moved with deglutition. Laboratory findings revealed normal thyrotropin, triodothyronine, and thyroxine levels. A sonography of the thyroid gland revealed a big solitary hypoechoic mass of 7.5x5.0 cm in the right lobe of the thyroid. No enlarged lymph nodes were found. A fine needle aspiration cytology of the right lobe of the thyroid was performed and revealed normal follicular cells and colloid and no neoplastic cells. A diagnosis of colloid goiter was suggested and an excision biopsy was advised to rule out neoplastic pathology. A lobectomy was performed. Upon analyzing the frozen section, a diagnosis of adenoma was suggested. The tissue was sent in formalin for a histopathological examination for further typification. Fat staining was not done as a diagnosis of adenolipoma was not suspected at that time. Grossly, the lobectomy specimen of the thyroid measured 7x5x4.5 cm. The external surface was smooth and encapsulated. The cut surface of the tumor was solid and grayish-white to yellow [Figure 1]. Microscopically, the solid tumor was separated from the adjacent compressed thyroid tissue by a thin fibrous capsule [Figure 2]. The tumor was found to be composed of follicular epithelial cells arranged in a microfollicular pattern. Trabeculae, sheets, and some hyperplastic follicles intermingled with mature adipose tissue [Figure 3]. Fat cells appearing as macrovacuolated cells were scattered among the follicular epithelial cells constituting about 40% of the tumor. A periodic acid shiff (PAS) stain was found to be negative. No degenerative changes were seen in the fatty component namely calcification, hemorrhage, or fibrosis. No cellular atypia was seen in either of the tumor components. There was no sign of vascular or capsular invasion. No adipose tissue was found outside the tumor. The diagnosis of adenolipoma of the thyroid gland was made. Immunohistochemistry showed a strong positivity for thyroglobulin.


Adenolipomas are not different from their usual counterparts clinically. They cause mainly compression symptoms and an increase in neck volume. [3],[4] The patients are usually euthyroid. In our case, the patient presented with a swelling in the neck with normal levels of T3, T4, and thyrotropin. An ultrasound revealed a large hypoechoic mass in the right lobe of the thyroid. Small amounts of adipose tissue are rarely seen in a normal thyroid gland adjacent to the capsule, in surrounding vessels, and in connective tissue septa. The adipose tissue has been described in non neoplastic conditions such as nodular hyperplasia, amyloid goiter, graves disease, lymphocytic thyroditis, and thyroid atrophy and neoplastic conditions such as adenoma, papillary carcinoma, and occasionally liposarcoma. [2],[3],[4],[5],[6],[7],[8] Adenolipomas differ from diffuse lipomatosis of the thyroid and amyloid goiter with fat cells in that they are well circumscribed and capsulated mass lesions. [4],[5]

The origin of adipose tissue in the thyroid gland is unclear. Some authors consider the presence of intrathyroid fat as a developmental anomaly that results from the entrapment of adipose tissue during encapsulation of the thyroid gland. [4],[8],[9] Others suggest metaplastic origin from fibroblasts due to chronic hypoxia. [2],[3],[4],[9] Trites reported a case of thyrolipoma associated with thymolipoma and a pharyngeal lipoma and noted that simultaneous presence of these tumors suggested a disturbance in the development of foregut. [6] Lipoadenoma was also described by Sheikh and found that distinguishing lipoadenoma of the thyroid gland from lipoadenoma of the parathyroid gland is very difficult and requires immunohistochemistry. Strong positivity for thyroglobulin confirm the origin to be the thyroid. [10] Our case fulfilled the criteria of thyroid adenolipoma revealing compressed thyroid tissue outside the capsule, a large number of follicles, and strong positivity for thyroglobulin. No raised serum calcium levels were found. Parathyroid hormone secretions were also within normal limits. Thus, the diagnosis of thyroid adenolipoma should be supported by ultrasound, histological, immunohistochemistry, and biochemical findings. This case is presented here because of its rare occurrence. These lesions are considered to be benign and treated surgically.


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