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CASE REPORT |
https://doi.org/10.5005/jp-journals-10088-11232 |
Atypical Parathyroid Adenoma with Multiple Brown Tumors: A Rare Case
1,4,5Department of Surgical Disciplines, All India Institute of Medical Sciences, New Delhi, India
2,3Department of Surgery, All India Institute of Medical Sciences, New Delhi, India
6Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
Corresponding Author: Ajay Mohan, Department of Surgical Disciplines, All India Institute of Medical Sciences, New Delhi, India, Phone: +91 9311470123, e-mail: ajaymay1592@gmail.com
How to cite this article: Mohan A, Aphale R, Dingoriya A, et al. Atypical Parathyroid Adenoma with Multiple Brown Tumors: A Rare Case. Indian J Endoc Surg Res 2024;19(1):17–20.
Source of support: Nil
Conflict of interest: None
Patient consent statement: The author(s) have obtained written informed consent from the patient for publication of the case report details and related images.
Received on: 28 February 2024; Accepted on: 25 March 2024; Published on: 17 June 2024
ABSTRACT
Objective: Present a case of an atypical parathyroid adenoma with extreme clinical features like multiple brown tumors and discuss the uncertainties in differentiating between a benign and malignant entity.
Background: The atypical parathyroid adenoma is purely a histological diagnosis. It is a parathyroid tumor with atypical histological features different from an adenoma but not similar enough to be considered as a carcinoma. It has an uncertain malignant potential.
Case description: We report the case of a 48‐year‐old woman, who presented with multiple swellings all over the bony areas of her body. Positron emission tomography computed tomography (PET CT) showed a fluorodeoxyglucose (FDG) avid lesion in the right thyroid lobe with multiple skeletal lesions. Further evaluation revealed hypercalcemia following which a Sestamibi scan was done. Diagnosis of primary hyperparathyroidism (PHPT) with right inferior parathyroid adenoma and associated multiple brown tumors in hypercalcemic crisis was made. The patient underwent focused right inferior parathyroidectomy and postoperatively, iPTH and calcium levels dropped significantly. The histopathological examination of the removed tissue concluded to be an “atypical” parathyroid adenoma. The atypical parathyroid adenoma is a very rare tumor, and the diagnosis is still a challenge, the outcome of patients is not well known yet, therefore close surveillance is important and must be done regularly.
Keywords: Atypical parathyroid adenoma, Browns tumor, Case report, Hypercalcemia, Hyperparathyroidism, Hypercalcemic crisis.
INTRODUCTION
One of the most frequent causes of hypercalcemia and hypercalcemic crisis is primary hyperparathyroidism (PHPT). It is an endocrine illness that is most usually due to parathyroid adenoma (80–85%), parathyroid hyperplasia (10–15%), or parathyroid cancer (PC) (1%).1 Atypical parathyroid adenoma is a lesion with suspicious clinical and histological features of PC, but it does not completely respect the World Health Organization (WHO) criteria for the diagnosis of PC.2 The real incidence of atypical parathyroid adenoma (APA) is unclear, however, it is a parathyroid tumor with aberrant histological characteristics that set it apart from adenomas while remaining too dissimilar to be classified as a carcinoma.1 There is no certainty about its malignant potential.
CASE DESCRIPTION
We report the case of a 48‐year‐old woman from Bihar, India, who was asymptomatic 2 years back when she noticed a swelling in her forehead, associated with pain with no history of variation in the size of the swelling. Three months later she developed another similar swelling on the right side of her jaw. Over the next few months, she developed similar swellings on other bony parts of her body (Fig. 1).
Fig. 1: Multiple brown tumors over the bony areas of the face (forehead and mandible)
She was initially evaluated in the line of multiple myeloma for which she underwent a emission tomography computed tomography (PET-CT) which showed fluorodeoxyglucose (FDG) avid 26 × 16 mm lesion in the right thyroid lobe with multiple skeletal lesions in the frontal bone, bilateral femur, pelvic bone, right mandible, maxilla and hard palate. During further workup, she was found to have hypercalcemia following which a Sestamibi scan was done. She was diagnosed with right inferior parathyroid adenoma and was planned for focused parathyroidectomy. There was no history of abdominal pain, flank pain, fracture anywhere, constipation, insomnia, or anxiety. On lab investigation, serum calcium level was found to be raised (12.8 mg/dL) with an iPTH value of 1881 pg/mL.
The cervical ultrasound revealed a right hyperechoic, heterogeneous parathyroid mass, measuring 2.5 × 1.5 × 1.8 cm in diameter with a normal thyroid gland, and the Technetium-99 Sestamibi‐Scintigraphy showed a large right inferior parathyroid adenoma. Diagnosis of PHPT with right inferior parathyroid adenoma and associated multiple brown tumors in hypercalcemic crisis was made.
Surgical Intervention
The patient underwent a focused right inferior parathyroidectomy. A parathyroid gland of size 3.5 × 3 cm was excised from the inferior pole of the right thyroid lobe. There was increased vascularity and it was adherent to surrounding tissues. The excised specimen weighed 8 grams. The postoperative PTH level dropped significantly to 17 pg/mL (preop value of 1881 pg/mL) and serum calcium to 8.5 mg/dL (preop value of 12.8 mg/dL). The cut section of the resected specimen is shown in the Figure 2.
Fig. 2: Cut section of the resected specimen of right inferior parathyroid adenoma
Histopathological examination of the specimen concluded an atypical parathyroid adenoma with the predominant arrangement in nests. There was evidence of capsular invasion without any extension into surrounding soft tissues or vital structures. There was no conclusive evidence of vascular or perineural invasion. There was no sheet-like arrangement, increase in mitotic activity, or any significant nuclear atypia or necrosis (Fig. 3). On immunohistochemistry, parafibromin expression is retained with a Ki67 labeling index of 1% (Fig. 4).
Fig. 3: Hematoxylin and Eosin (H and E) stained sections of the “atypical” parathyroid adenoma showings cells predominantly arranged in nests, at different maginifications
Figs 4A to E: On immunohistochemistry, showing: (A) Retained parafibromin expression (× 400); (B) Ki 67 index around 1% (× 400); (C) RB expression (× 200); (D) Galectin negative (× 200); (E) BCL2 expression (× 40)
Follow-up
On the second postoperative day, the patient complained of a tingling sensation all over her body (Hungry bone syndrome) for which she was started on intravenous calcium infusion. Her calcium level was normalized within the next 7 days and was discharged on oral calcium supplements. Follow-up after one month revealed no new symptoms and a normal calcium and iPTH level.
The atypical parathyroid adenoma is a very rare tumor. The right diagnosis itself is a great challenge. The long-term outcome of such patients is not yet studied extensively, so close surveillance is important.
DISCUSSION
Parathyroid gland tumors are uncommon, affecting between 0.1% and 0.3% of the general population.3 It is well established that APA causes 1.2–1.3% of PHPT but its malignant potential is still a mystery.1 It typically affects females (1.5:1 ratio), is more prevalent in later life (median age 44 years), and develops a decade before benign parathyroid disorders.3 Clinically, the profile is comparable to that of severe hypercalcemia. Anorexia, asthenia, anxiety, constipation, nausea, vomiting, bone pain, nephrolithiasis, hypertension, and occasionally depression are among the symptoms.4
Dysphonia and dysphagia, which are uncommon in benign parathyroid disorders, are warning indicators of local compression. Additionally, palpable neck masses are frequently found in APA patients (15% on physical examination), usually, they are more than 2.5 cm.3
It typically goes hand in hand with severe hypercalcemia and noticeably high PTH levels. The plasma level of human chorionic gonadotropin (HCG), which has a normal range of 4 IU/L for non-pregnant females or males, may also be raised, and alkaline phosphatase (ALP) activity may also be above the upper normal range.5 The first line of radiological investigation is an ultrasound of the neck, which describes the mass—whether solid or cystic—along with measurements and its relationship to surrounding tissues. Sestamibi scans or Single-photon emission computed tomography (SPECT/CT) can be used to localize the lesion before surgery.6–8
The tumor is removed en bloc through surgery, the sole treatment available for the condition. The only way to diagnose APA is through a histopathological analysis. This further sets it apart from similar differential diagnoses such as benign typical parathyroid adenoma or PC. The APA is a parathyroid tumor, according to WHO, that does not exhibit locally advanced growth or metastases but may exhibit cell atypia, fibrotic tissue, trabecular growth, fibrotic capsular involvement, and increased mitotic rate.9 Immunohistochemistry and molecular biology are other helpful tests for diagnosis.
Sometimes, the clinical course of APA and parathyroid carcinoma cannot be distinguished without close monitoring. Parathyroid cancer has a substantially higher recurrence rate (>50%) and reappears 2–3 years following surgery.10 Regarding the APA, numerous datasets that looked at the long-term result did not detect any recurrence after a median follow-up of 5 years.11 However, there are currently no specific guidelines for the surveillance rhythm following parathyroid surgery.12
CONCLUSION
It is quite difficult to diagnose the atypical parathyroid adenoma since it resembles both the conventional parathyroid adenoma and cancer. Furthermore, little research has been done in depth regarding patients’ long-term outcomes. As a result, they must be regarded as “tumors of uncertain malignant potential,” which justifies ongoing vigilant monitoring and stringent follow-up.
ORCID
Ajay Mohan https://orcid.org/0000-0002-2125-5585
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