Dermatologic manifestations of parathyroid-related disorders

Dermatologic Manifestations of Endocrine Disorders

Endocrine disorders are known to involve all organ systems of the body, including the skin. The cutaneous manifestations of endocrine disorders can range from common findings such as acanthosis nigricans, pretibial myxedema, acne, hirsutism, hyper or hypopigmentation to rare cutaneous findings such as miliaria rubra, calciphylaxis, lentigines, and calcinosis cutis. These cutaneous symptoms can sometimes be the presenting symptoms or can even be pathognomonic of the underlying endocrine condition. In some cases, the cutaneous symptoms from an underlying endocrine abnormality may be the most prominent. These symptoms can significantly affect the quality of life of individuals. Often, individuals may seek health care from a dermatologist or primary care physician for isolated skin symptoms. Therefore, it is imperative for physicians to recognize the skin symptoms as the manifestation of the endocrine disorder for prompt diagnosis and treatment of the underlying endocrine disorder.

Disorders of Calcium Metabolism: Hypocalcemia and Hypercalcemia

Calcium (Ca⁺²) is a divalent cation that plays a critical role in numerous body functions such as skeletal mineralization, signal transduction, nerve conduction, muscle contraction, and blood coagulation. Ca⁺² metabolism is linked to magnesium (Mg⁺²) and phosphate metabolism. Ca⁺² homeostasis is dependent on intestinal absorption, bone turnover, and renal reabsorption. The hormonal regulators of these processes are the parathyroid hormone (PTH), calcitriol {1,25-dihydroxyvitamin D [1,25(OH)₂D]}, and serum ionized Ca⁺². Cloning of the Ca⁺²-sensing receptor (CaSR) has greatly advanced the understanding of Ca⁺² metabolism. Disorders of Ca⁺² metabolism are easily recognized because Ca⁺² is included in routine chemistry panels. Measurement of ionized Ca⁺² is the preferred way to ascertain the diagnosis of hypocalcemia and hypercalcemia.

Signs and Symptoms of Hypoparathyroidism

Hypoparathyroidism is associated with a spectrum of clinical manifestations in the acute and chronic settings, from mild to debilitating. Although the acute symptoms of hypocalcemia are primarily due to neuromuscular irritability, the chronic manifestations of hypoparathyroidism may be due to the disease itself or to complications of therapy or to both. The chronic complications of hypoparathyroidism can affect multiple organ systems, including the renal, neurologic, neuropsychiatric, skeletal, and immune systems. Further research is needed to determine the pathophysiology of complications in hypoparathyroidism and whether interventions can decrease the risk of these complications.

Childhood parathyroid adenoma: a rare but important cause of nephrolithiasis

Primary hyperparathyroidism is very rare in children and adolescents. The management of a 12-year-old boy with renal calculi due to parathyroid adenoma is discussed. The single tumor after localization with sestamibi scintigraphy and SPECT-CT scan was excised with amelioration of symptoms. The case is reported due to the rarity of the disease and successful unilateral exploration. The association with hypopigmented areas of skin has also not been previously reported in literature.

Corneal xanthogranuloma in association with multiple endocrine neoplasia 1: A clinicopathologic case report and review of the literature

Juvenile xanthogranuloma (JXG) is a benign inflammatory condition of uncertain pathogenesis. It is characterized by skin and ocular involvement – typically in the iris – in children. It has been reported in older age groups and has been also observed to involve other ocular structures such as the cornea and conjunctiva.

In this case report, we are presenting an extensive right eye corneal lesion in a 43-year old male which showed the typical histopathological feature of JXG and in association with multiple endocrine neoplasia (type 1). Similar cases in the English-language literature have been also reviewed.

The effect of parathyroid hormones on hair follicle physiology: implications for treatment of chemotherapy-induced alopecia

Parathyroid hormone (PTH) and parathyroid hormone-related protein (PTHrP) influence hair follicles through paracrine and intracrine routes. There is significant evidence that PTH and PTHrP influence the proliferation and differentiation of hair follicle cells. The PTH/PTHrP receptor signalling plays an important role in the hair follicle cycle and may induce premature catagen-telogen transition. Transgenic mice with an overexpression or blockade (PTH/PTHrP receptor knockout mice) of PTHrP activity revealed impaired or increased hair growth, respectively. Some findings also suggest that PTHrP may additionally influence the hair cycle by inhibiting angiogenesis. Antagonists of the PTH/PTHrP receptor have been shown to stimulate proliferation of hair follicle cells and hair growth. A hair-stimulating effect of a PTH/PTHrP receptor antagonist applied topically to the skin has been observed in hairless mice, as well as in mice treated with cyclophosphamide. These data indicate that the PTH/PTHrP receptor may serve as a potential target for new (topical) hair growth-stimulating drugs, especially for chemotherapy-induced alopecia.

Novel nonsense GNAS mutation in a 14-month-old boy with plate-like osteoma cutis and medulloblastoma

Plate-like osteoma cutis (PLOC) is a dermatological disorder characterized by superficial ossification and rarely occurs without any underlying tissue abnormalities or pre-existing calcification. The hereditary form of PLOC is mainly due to inactivating mutation in the GNAS gene. Inactivating mutation of the GNAS gene is associated with several diseases, which commonly manifest heterotopic ossification and hormonal resistance; however, the development of malignant neoplasm has never been reported. Herein, we report a case of a patient with a novel nonsense mutation in the GNAS gene, who presented with concurrent PLOC and medulloblastoma.

Extremely high parathyroid hormone concentrations associated with pityriasis rubra pilaris and monoclonal gammopathy of unknown significance: a clinical dilemma

We present a case with extremely high parathyroid hormone (PTH) concentrations in the order of hundred thousands accompanied by dermatological and hematological diseases. After several diagnostic interventions, no malignancy could be demonstrated except monoclonal gammopathy of unknown significance. The dermatological findings were taken to be manifestations of the hematological disease. Since the first serum intact PTH concentration of the patient was found to be higher than 2500 pg/ml, dilution study was performed and found to be 215,977 pg/ml. The high concentration of serum PTH was taken to be falsely high due to assay interference. This concentration was checked from three different paths; a test for linear dilution was performed, the test was repeated with another method and the sample was treated to remove or inhibit interfering substances. The results were compatible with endogenous antibody interference, presumed to be a result of monoclonal gammopathy. The extremely high PTH concentrations were not only due to assay interference, but also secondary hyperparathyroidism, which was evident by the decrease in PTH concentrations with calcium and vitamin D treatments.

Skin lesions in hereditary endocrine tumor syndromes

OBJECTIVE

To review the main cutaneous manifestations of hereditary endocrine tumor syndromes and discuss currently known molecular mechanisms involved in their pathogenesis.

METHODS

On the basis of our collective experience and a comprehensive MEDLINE literature search of the English-language literature published between January 1957 and September 2010 using the search terms "skin," "cutaneous," "multiple endocrine neoplasia," "Carney complex," and "McCune-Albright syndrome," we reviewed the dermatologic findings in multiple endocrine neoplasia type 1 and type 2, Carney complex, and McCune-Albright syndrome.

RESULTS

Although the category of hereditary endocrine tumor syndromes consists of a broad spectrum of conditions, only the aforementioned few are prominently associated with cutaneous features. Because the cutaneous findings associated with these diseases are generally benign, they are often ignored or dismissed as ancillary findings in the context of severe systemic involvement. Accordingly, the pertinent literature is relatively scarce and often fails to provide a comprehensive insight about this issue. Nevertheless, timely recognition of such dermatologic manifestations may have a critical role in the early diagnosis and appropriate management of the related syndromes. Moreover, specific genotype-phenotype correlations may convey important prognostic implications.

CONCLUSION

Many physicians are unfamiliar with the cutaneous findings in the hereditary endocrine tumor syndromes described in this review. Nonetheless, knowledge of their existence can have a major role in establishing an early diagnosis of these syndromes and determining the patient's prognosis.

Rapidly growing collagenomas in multiple endocrine neoplasia type I

Patients with multiple endocrine neoplasia type I (MEN-I) frequently develop skin lesions including collagenomas, angiofibromas, and lipomas. We report a patient with MEN-I who exhibited rapid growth of multiple collagenomas after pancreatic enucleation of a vasoactive intestinal peptide-secreting tumor (VIPoma) and excision of multiple pancreatic masses. Five of the collagenomas were protuberant, with the bulk of the lesion protruding above the skin. Histologic analysis of the collagenomas revealed broad collagen bundles in a haphazard arrangement and decreased elastic fibers. Rapid growth of protuberant collagenomas appears to be unusual in MEN-I, but we suggest that MEN-I be considered in patients with apparent eruptive collagenoma.