Parathyroid carcinomas, a rare entity, accounts for less than 1 % 4,5
of all cases of primary hyperparathyroidism. A higher incidence has been reported in Japan and Italy where it rises up to 5-5,2%. 6,7
It is habitually a sporadic disease, but familial cases have been described.
Parathyroid carcinoma occurs equally in men and women, while benign parathyroid disease predominates in women by a ratio of 3-4:1.
The average age of diagnosis is the fourth decade of life whereas for benign adenomas the average age is thirty 8
. The 3 patients treated at our institution were respectively 35, 58, 76 years old, 2 women and 1 man
Paratyhyroid carcinomas have been described in 15% of hyperparathyroidism-jaw tumor (HPT-JT) syndrome, a rare autosomal disorder. In HPT-JT, ossifying fibromas of the maxilla and mandible are seen in 30 % of cases9
. Less commonly, kidney lesions including cysts, polycytic disease, harmartomas or Wilm's tumor can be present.
Although parathyroid carcinomas are not a feature of multiple endocrine neoplasia type 1 (MEN 1), recently 10-11
parathyroid carcinomas have been described in MEN 1. According to our Knowledge, only one case of parathyroid carcinoma has been reported in MEN 2 a syndrome 12
More than 90% of parathyroid carcinomas (PCA) are functional, and as such, the clinical features are due primarily to the effects of markedly elevated serum PTH and calcium levels. The most frequent complaints are weakness, fatigue, anorexia, nausea, vomiting, loss of weight, dyspepsia, constipation, headaches, polydipsia and polyuria. Bone, joint, muscular pain, pathological fractures, and renal stones are frequent when hyperparathyroid state is severe. Recurrent severe pancreatitis, anemia and peptic ulcer disease can also occur. Among our 3 patients, 2 were symptomatic. One patient experienced fatigue, ankle and knee pain and the other fatigue, polyuria and polydipsia.
All those clinical signs are unspecific and often lead to a delayed diagnosis; furthermore even with a hypercalcaemia biologically proven, diagnosis may be missed. This was the case for all our patients before referral; all of them have been treated in the setting of a longstanding disease with a tumor size ranging from 4.5 cm to 7 cm.
A palpable mass in the neck is found in 30-76% of patients with parathyroid carcinoma 13
. This clinical finding can help to differentiate between a benign and a malignant parathyroid disease; indeed fewer than 5% of patients with benign disease have a palpable neck mass 14
. The American national cancer data base 15
confirmed in a report of 286 PCA a median size of 3.3 cm. Despite this size, we would like to underline the fact that, due to intrathoracic localization, a palpable mass was not found in 1 of our patients.