Primary hyperparathyroidism is the third most common disease of the endocrine system. It is characterized by an increase in parathyroid hormone, hypercalcemia, hypercalciuria, hypophosphatemia. Symptoms include polyuria, bone pain, weakness, and constipation. In most cases, primary hyperparathyroidism is caused by solitary parathyroid adenoma — 85%. Other causes include hyperplasia (5%), multiple adenomas (<5%), and cancer (<1%). However, particular attention in this article is paid to two causes of primary hyperparathyroidism: parathyroid adenoma and cancer, as they are of high interest both from a molecular point of view and from the clinical features of these tumors. In addition, these tumors overlap in their symptoms and signs and the diagnosis is often made only after histological examination. In total, we identified 2700 articles, of which 66 met the inclusion criteria. The 66 included studies were topical for tumor lesions of the parathyroid gland. They were held between 1997 and 2022. This review emphasizes the importance of further research of the molecular features of these diseases and, possibly, targeted treatment options, since, for example, in cancer, even with R0 resection, the risk of recurrence is high. The article also focuses on the issues of the new World Health Organization 2022 classification of tumor lesions of the parathyroid gland, which is also important for a unified study of these tumors.