Primary hyperparathyroidism with intrathyroidal location of parathyroid adenoma

Primary hyperparathyroidism is a common endocrine disease with high morbidity and mortality from all causes. The disease can be asymptomatic and for a long time remain undiagnosed, which leads to untimely surgical treatment, increases the risks of development and progression of severe disabling complications and worsens patients prognosis. In clinical practice there are certain difficulties in diagnosing this pathology. One of the urgent problems is the search for the source of parathyroid hormone hyperproduction, especially in case of atypical location of paraаdenoma. The most common atypical locations of altered parathyroid glands are thymus, retroor paraesophageal space, retropharyngeal space, mediastinum and thyroid gland. The frequency of intrathyroidal masses of parathyroid glands, in the thyroid parenchyma or under its capsule, ranges on average from 2 to 3%, but according to some authors can reach 18–22%. With such localization of paraadenomas there is a need for their differential diagnosis, first of all, with nodular formations of the thyroid gland. In addition, the absence of additional laboratory studies parathormone and calcium blood levels does not allow timely suspicion of the disease, and cytologic examination of the material obtained by fine-needle aspiration puncture biopsy does not allow reliable differentiation of the altered parathyroid gland. This article presents a clinical case of a patient with primary hyperparathyroidism with intrathyroidally located parathyroid adenoma, for a long time long identified as a “nodular goiter,” and provides a brief review of the methods that identify an intrathyroidally located parathyroma. Despite the abundance of diagnostic methods in visualization of intrathyroidal parathyroid glands, today the most appropriate seems to be expert ultrasound examination with assessment of the parathyroid hormone level in a washout after fine-needle aspiration, supplemented, if necessary, by scintigraphy and single-photon emission computed tomography combined with computed tomography or multispiral computed tomography.