Short report "About a rare cause of primary hyperparathyroidism"

M. Mlika et.al / Int J Cur Bio Med Sci. 2011; 1(2): 47 - 48.

Figure 1: a/ Proliferation of homogeneous water-clear cells
arranged in sheets or nests b/ Intra-cytoplasmic clear
vacuoles

3.Discussion

Primary hyerparathryoidism may be familial or sporadic. In case
of familial hyperparathyroidism, microscopic examination
reveals principal cell hyperplasia and is observed particularly in
case of type I and III multiple endocrinopathies. In case of
sporadic hyperparathyroidism, microscopic examination reveals
adenoma or clear cell hyperplasia. This last entity is rare and is
few documented. Initially, it was described by Albright in 1938. Its
frequency seems to be less than 1% of all primary hyperplasia. It
is mainly observed in men and never associated to a multiple
endocrinopathy [1]. It is characterized by an important increase
of the parathyroid parenchymal mass, the total weight of the four
glands can be more than 100 g can be manifested grossly by a
lesion mimicking an adenoma like the case presented. The
particularity of this observation consists in the attempt of ectopic
glands. In the opposition to principal cell hyperplasia, upper
glands are visibly bigger than the inferior ones. these glands are
soft in consistency with a chocolate like color. They are sometimes
the site of haemorrhage or cysts [3]. Microscopic examination
shows a monotonous proliferation of big clear cells with clear
cytoplasm [1]. This lesion must be distinguished from clear cell
adenoma or principal cell hyperplasia with a clear cell component
ad a parathyroid metastases of a clear cell renal carcinoma. The
distinction from an adenoma can be challenging in some cases. In
fact, radiologic findings showed multiple adenomas in our case.
Otherwise, the simultaneous attempt of three glands, the absence
of atrophic or normal parathyroid parenchyma justify the
diagnosis of parathyroid hyperplasia. [2]. Lawrence and
colleagues proved in a retrospective study of 18 cases of
hyperplasia, that nuclear pleomorphism in adenomas, the
nodular architecture of hyperplasia represent criteria of
differentiation that is statistically significant [4]. Principal cell
hyperplasia is characterized by the presence of principle cells
mixed with other types of cells. Some authors reported that
principal cell hyperplasia is an initial stage of clear cell
hyperplasia [5]. Clear cell carcinoma of the parathyroid gland is
characterized by the invasion of the adjacent tissue.
Microscopically, the capsular invasion, vascular emboles, atypia
and mitoses (> 5 mitoses/ 50 champs) are the major signs of
malignancy [2]. A metastatic localization of a renal carcinoma
could be suspected according to the clinical features and

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