<b><br>Introduction:</b> Primary hyperparathyroidism (PHPT) is mainly caused by parathyroid adenoma (PA). Rare variants of PA, weighing >2.0-3.5 g are called \"large\" or \"giant\" adenomas and account for about 1.5% of all PA.</br> <b><br>Aim:</b> The aim of this study was to compare normal-sized and large parathyroid lesions identifying risk factors for severe hypercalcemia.</br> <b><br>Materials and methods:</b> 27 patients with PHPT and parathyroid lesion ≥2.0 cm3 (study group) were compared with 73 patients with PHPT and lesion < 2.0 cm³ (control group). In both groups, the majority were women (81.5% - study group, 90.5% - control group, gender ratios 4.4:9.1, respectively). The patients were examined preoperatively and postoperatively: PTH, creatine, calcium, and phosphate serum and urine concentrations, and calcidiol serum levels were assessed. Preoperative ultrasonography (US) was performed.</br> <b><br>Results:</b> Patients with larger parathyroid lesions had signifficantly higher PTH and calcium serum concentrations and lower serum phosphate and calcidiol concentrations. There were no statistically significant differences in the concentration of creatine in serum and urine, calciuria, or tubular reabsorption of phosphorus (TRP). US relatively underestimated the parathyroid volume by about 0.3-0.4 mL (10% in larger lesions and 43% in smaller ones).</br> <b><br>Conclusions:</b> Due to higher PTH and calcium levels, larger parathyroid adenomas may constitute a higher risk of severe hypercalcemia. In general, US underestimated the parathyroid volume.</br>.

A hypercalcemic crisis is a rare therapeutic emergency. However, it should not be overlooked, particularly during pregnancy, as it is associated with significant maternal and fetal morbidity and mortality. The most frequent etiology, including in pregnant women, is primary hyperparathyroidism. Knowledge of calcium-phosphate metabolism during pregnancy is important for understanding and interpreting the clinicopathological abnormalities observed in parathyroid pathology. Despite the expert consensus statement on parathyroid pathology issued by the European Society of Endocrinology, management of hypercalcemic crises remains poorly codified, particularly in pregnant women. Diagnostic examinations and hypocalcemia treatments are generally not recommended during pregnancy; however, it may be necessary to optimize preparation for surgery. Notably, surgery is the treatment of choice, particularly during pregnancy, when it should ideally be performed during the 2nd trimester. Therefore, a multidisciplinary approach is necessary. A consensus among European experts recommends systematic early detection of hypercalcemia during early pregnancy.

BACKGROUND: Parathyroid adenoma is the most common cause of hypercalcemia and rarely leads to a hypercalcemic crisis, which is an unusual endocrine emergency that requires timely surgical excision.
METHODS: A 67-year-old male was admitted to the ER of the Euroclinic Hospital, Athens, Greece, because of elevated calcium levels and a palpable right-sided neck mass, which were accompanied by symptoms of nausea, drowsiness, and weakness for six months that increased prior to our evaluation. A gradual creatinine elevation and decreasing mental state were observed as well. The initial laboratory investigation identified severely elevated serum calcium (3.6 mmol/L) levels consistent with a hypercalcemic crisis (HC) and parathyroid hormone PTH (47.6 pmol/L) due to primary hyperparathyroidism. Neck ultrasonography (USG) identified a large, well-shaped cystic mass in the right thyroid lobe. With a serum calcium concentration of 19.5 mg/dL and a PTH of 225.3 pmol/L, the patient underwent partial parathyroidectomy and total thyroidectomy, which decreased serum calcium and PTH to 2.5 mmol/L and 1.93 pmol/L, respectively. Histology revealed a giant intrathyroidal cystic parathyroid adenoma, which was responsible for the hypercalcemic crisis. Postoperatively, the patient developed severe biochemical and clinical hypocalcemia, with calcium concentrations as low as 1.65 mmol/L, consistent with hungry bone syndrome (HBS), which was treated with high doses of intravenous calcium gluconate and oral alfacalcidol, and a slow recovery of serum calcium. After discharge, parathyroid function recovered, and symptomatology resolved entirely in more than one month.
CONCLUSIONS: We present a case involving an exceptionally large intrathyroidal parathyroid adenoma that is characterized by clinical manifestations that mimic malignancy. The identification and treatment of such tumors is challenging and requires careful preoperative evaluation and postoperative care for the risk of hungry bone syndrome.

Ewing\'s sarcoma (ES) is a rare malignancy of adolescence that usually presents with clinically apparent disease involving long bones, brought to attention by trauma and/or fractures. Hypercalcemia of malignancy is a well-known phenomenon; however, hypercalcemia is exceptionally rare in ES. This case report discusses a 20-year-old lady who experienced chronic bone pains in her hip and lower limbs, ultimately leading to a hypercalcemic crisis. We emphasize the importance of considering ES as a potential cause of hypercalcemia, highlighting the mechanism, diagnostic and therapeutic challenges, the associated poor prognosis, and the necessity for a multidisciplinary approach to managing the condition.

UNASSIGNED: Atypical parathyroid tumors (APTs) are rare entities. We report the case of a patient with multiple APT presenting with extrapyramidal symptoms and a delayed hypercalcemic crisis.
UNASSIGNED: A 72-year-old man presented to a tertiary referral center\'s emergency room (ER) following two episodes of temporary loss of consciousness. He had a history of ideomotor sluggishness, lethargy, extrapyramidal symptoms and dysphagia, which started 6 months prior. Serum calcium levels at presentation were normal. Four days later the patient developed a rapidly evolving respiratory failure requiring orotracheal intubation, severe hypercalcemia (up to 19.8 mg/dL) and increased serum parathyroid hormone (PTH) (151 pmol/L). A neck ultrasound (US) showed two lesions posteroinferiorly to the right and left thyroid lobe. Since hypercalcemia proved to be refractory to medical therapy, the patient underwent urgent bilateral neck exploration with subtotal parathyroidectomy for suspect parathyroid carcinoma (PC). Histopathological examination showed three nodular lesions consistent with a diagnosis of APT in each excised parathyroid. Four months after surgery, the patient is alive and well with no signs of recurrence. Neurological follow-up visits documented the absence of extrapyramidal signs.
UNASSIGNED: Our patient showed an unusual presentation of primary hyperparathyroidism (PHPT) sustained by multiple concurrent APTs. A low suspicion threshold should be maintained to avoid delay in diagnosis. The present case adds to the body of literature on APTs, contributing to a greater understanding of this rare disease.

Hyperparathyroidism-induced hypercalcemic crisis (HIHC) is an unusual state of marked progressive primary hyperparathyroidism (PHPT). Patients have severe hypercalcemia and may have severe symptoms such as kidney failure, acute pancreatitis, and mental changes. PHPT is due to the presence of a single gland adenoma/ disease in 80 to 85%; parathyroid carcinoma is reported in <1%. Among patients with adenoma, atypical parathyroid tumor can be found infrequently. Parathyroidectomy is the only curative approach for PHPT. In this report we present three cases of HIHC due to giant parathyroid adenomas (GPAs), one of them with histopathological characteristics of an atypical parathyroid tumor, with satisfactory evolution after parathyroidectomy.
La crisis hipercalcémica inducida por hiperparatiroidismo (HIHC) es un estado inusual de hiperparatiroidismo primario progresivo y marcado (HPTP). Los pacientes tienen hipercalcemia grave y pueden tener síntomas graves como insuficiencia renal, pancreatitis aguda y cambios mentales. El HPTP se debe a la presencia de un adenoma/enfermedad de una sola glándula en 80 a 85%; el carcinoma de paratiroides se informa en <1%. Entre los pacientes con adenoma, el tumor paratiroideo atípico se puede encontrar con baja frecuencia. La paratiroidectomía es el único abordaje curativo del HPTP. En este reporte presentamos tres casos de HIHC por adenomas paratiroideos gigantes (APGs), uno de ellos con características histopatológicas de tumor paratiroideo atípico, con evolución satisfactoria luego de paratiroidectomía.

Hypoparathyroidism requires management with both calcium supplementation and active vitamin D to avert a state of hypocalcemia. During late gestation and the postpartum period (specifically lactation), there is an under-recognized, yet intriguing occurrence of apparent \'pseudohyperparathyroidism\', whereby supplementation dosages may need to either be reduced or discontinued, to prevent hypercalcemia. The explanation for this apparent phenomenon of improved parathyroid status (\'remission\' or \'resolution\') is incompletely understood; the purpose of this review is to analyze the case reports of this enigma within the medical (and grey) literature, providing an overall pathophysiological explanation and recommendation for the management of such patients. A literature search was conducted through PubMed/Medline, CINAHL, Cochrane Library Database, Scopus, UpToDate, Google Scholar, and the grey literature without a time-restricted period, analyzing all available articles within the literature describing an apparent improvement in parathyroid status in late-gestation and postpartum (lactating) females. Non-hypoparathyroid case reports were also included to further analyze and synthesize an overall likely pathophysiological explanation. Through the literature search, 24 papers were identified covering such a phenomenon in patients with hypoparathyroidism, alongside multiple additional reports of a similar occurrence in patients without underlying hypoparathyroidism. The pathophysiology is believed to occur due to the placental production of parathyroid hormone-related peptide (PTHrP) during gestation, with further production from the lactating mammary glands during the postpartum period. A typical pattern is observed, with increased PTHrP and suppressed PTH throughout both gestation and lactation (present in both normal and hypoparathyroid subjects). The concept of PTHrP-induced hypercalcemia is further demonstrated in patients without hypoparathyroidism, including subjects with placental hypersecretion and mammary gland enlargement. It is evident that patients with hypoparathyroidism may require a dosage reduction during late gestation and lactation, due to the risk for hypercalcemia. In addition to patients with hypoparathyroidism, this pathophysiological phenomenon occurs in unsuspecting patients, demonstrating the need for all clinicians in contact with pregnant females to be aware of this uncommon - yet perilous - occurrence.

A hypercalcemic crisis due to primary hyperparathyroidism is a life-threatening condition. We herein report a 71-years-old man with hypercalcemic crisis due to primary hyperparathyroidism with parathyroid adenoma. Generally, hemodialysis or continuous hemodiafiltration using calcium-free or low-calcium dialysate is performed early for hypercalcemic crisis. In this case, continuous hemodialysis with a common calcium concentration dialysate improved the hypercalcemic crisis, and parathyroidectomy was performed. The patient recovered sufficiently. Prediction of hypercalcemia crisis, appropriate introduction and methods of blood purification therapy, and timing decisions for parathyroidectomy are required for therapeutic management of hypercalcemic crisis with parathyroid adenoma.

(1) Background: Parathyroid cystic adenomas (PCA) are rare entities representing only 0.5-1% of parathyroid adenomas, accounting for 1-2% of cases of primary hyperparathyroidism (PHPT). The purpose of this study was to compare classical and functional/secreting cystic parathyroid lesions and identify risk factors for severe hypercalcemia; (2) Methods: A total of 17 patients with PHPT and parathyroid cysts (study group) were compared with the group of 100 patients with hyperparathyroidism caused by adenoma or hyperplasia (control group). In both groups the majority were women (88% vs. 12%, with gender ratio 7, 3:1). The patients were examined preoperatively and postoperatively: PTH, creatine, calcium and phosphate serum and urine concentrations and calcidiol serum levels were assessed; (3) Results: Patients with parathyroid cyst had statistically higher PTH and calcium serum concentration, higher calciuria and lower serum phosphate concentration. There were no statistically significant differences in the concentration of creatine in serum and urine and tubular reabsorption of phosphorus (TRP); (4) Conclusions: Due to higher PTH and calcium levels, cystic parathyroid adenomas could be one of the rare risk factors for severe hypercalcemia and hypercalcemic crisis which can be life threatening.

BACKGROUND: In most cases of parathyroid adenoma (PA), it is not palpable and physical examination shows no remarkable findings. Hence diagnosis requires an index of suspicion. The current paper describes four cases of severe hypercalcemia secondary to PA.
METHODS: Case 1 - 29 years old Sudanese female with history of nausea/vomiting, fatigue, loss of appetite and bone aches. She had large palpable left lower neck swelling, and high calcium and PTH. Ultrasound (US) neck and SPECT/CT scan after sestamibi injection showed left inferior PA. Case 2-73 years old Sudanese male referred with history of abdominal pain and flatulence. He had severely high calcium, elevated parathormone (PTH), and high 24-hour urine calcium. US and SPECT/CT showed a left inferior PA. Case 3-54 years old Bangladeshi male, referred with history of renal colic/urolithiasis. Laboratory results showed severely high calcium and PTH levels. US and SPECT/CT scan showed right inferior PA. Case 4-35 years old Tunisian female, 12 weeks pregnant, referred with recurrent nausea and vomiting of increasing frequency from the second week of pregnancy. Laboratory tests revealed severe hypercalcemia and high PTH. US showed two parathyroid lesions.
CONCLUSIONS: The patients were admitted as emergency cases and investigations diagnosed severe hypercalcemia secondary to PA. All patients underwent neck exploration and PA excision. Histology confirmed PA. The four cases were swiftly assessed and treated before progressing into the more serious hypercalcemic crisis which can lead to grave consequences, particularly in the case of the pregnant female. All patients recovered with no complications and were clinically well with normal calcium level on follow up.
CONCLUSIONS: Severe hypercalcemia must be swiftly and thoroughly assessed to prevent the more serious hypercalcemic crisis. Clinicians need to be suspicious of parathyroid adenoma as a probable cause. Severe hypercalcemia is often accompanied with vomiting, and in pregnant females, this could be mistaken for hyperemesis gravidarum. Excision of the parathyroid adenoma treats the condition and follow up of serum calcium and PTH confirms the favorable outcome of surgery.