Hypercalcitoninaemia in a patient with urticaria pigmentosa. A possible cause of diarrhoea

Medullary thyroid cancer: management guidelines of the American Thyroid Association

BACKGROUND

Inherited and sporadic medullary thyroid cancer (MTC) is an uncommon and challenging malignancy. The American Thyroid association (ATA) chose to create specific MTC Clinical Guidelines that would bring together and update the diverse MTC literature and combine it with evidence-based medicine and the knowledge and experience of a panel of expert clinicians.

METHODS

Relevant articles were identified using a systematic PubMed search and supplemented with additional published materials. Evidence-based recommendations were created and then categorized using criteria adapted from the United States Preventive Services Task Force, Agency for Healthcare Research and Quality.

RESULTS

Clinical topics addressed in this scholarly dialog included: initial diagnosis and therapy of preclinical disease (including RET oncogene testing and the timing of prophylactic thyroidectomy), initial diagnosis and therapy of clinically apparent disease (including preoperative testing and imaging, extent of surgery, and handling of devascularized parathyroid glands), initial evaluation and treatment of postoperative patients (including the role of completion thyroidectomy), management of persistent or recurrent MTC (including the role of tumor marker doubling times, and treatment of patients with distant metastases and hormonally active metastases), long-term follow-up and management (including the frequency of follow-up and imaging), and directions for future research.

CONCLUSIONS

One hundred twenty-two evidence-based recommendations were created to assist in the clinical care of MTC patients and to share what we believe is current, rational, and optimal medical practice.

Gastrointestinal abnormalities and involvement in systemic mastocytosis

Recent studies have shown that involvement of the gastrointestinal tract is much more frequent than originally reported in patients with systemic mastocytosis. Seventy percent to 80% of patients with systemic mastocytosis are found to have gastrointestinal symptoms when a careful history is taken, and abnormalities in the gastrointestinal tract are frequently detected by endoscopic studies, functional studies of absorption, and barium studies. Because of the rarity of the disease, there are few prospective studies of gastrointestinal involvement, so the actual frequency of upper and lower gastrointestinal lesions is unknown. Furthermore, there have been no studies correlating endoscopic abnormalities of the lower gastrointestinal tract with the presence or absence of diarrhea, which is a frequent symptom (mean, 43% [range 14%-100%]). A review of gastric acid studies reveals that a proportion of patients develop gastric acid hypersecretion because of the hyperhistaminemia, which can result in ulcer disease that in turn can cause dyspeptic pain, small intestinal mucosal damage, and malabsorption. In some patients gastric acid hypersecretion in the range seen in Zollinger-Ellison syndrome can develop. A number of studies suggest that the prevalence of peptic ulcer disease has been underestimated in these patients and is certainly higher than the general population. The exact physiologic basis for the diarrhea or nondyspeptic abdominal pain remains largely unknown in these patients. Whereas some studies suggest small intestinal mucosal abnormalities are responsible for most cases of malabsorption not associated with gastric acid hypersecretion, this supposition also remains unproven. Hepatomegaly, portal hypertension, splenomegaly, and ascites occur frequently in patients with systemic mastocytosis, especially those with category II through IV disease. Whereas the histology of the liver and spleen and alterations in hepatic function studies have been well studied, the pathogenesis of each of these abnormalities has not been well studied, and almost all the information comes from a few well-studied case reports.

Aspirin idiosyncrasy in systemic mast cell disease: a new look at mediator release during aspirin desensitization

OBJECTIVE

To report the clinical responses and mediator-release profiles of an aspirin-sensitive man with systemic mast cell disease during aspirin desensitization.

MATERIAL AND METHODS

We quantified the release of six mediators during aspirin desensitization.

RESULTS

Although aspirin was administered cautiously with an initial dose of 20 mg, successful aspirin desensitization necessitated complete monitoring and resuscitation capabilities of a medical intensive-care unit for 4.5 days because of frequent, severe anaphylactoid responses. To our knowledge, this is the first report of a pronounced increase in plasma levels of the vasodilator peptide calcitonin gene-related peptide during episodes of aspirin-induced hypotension. Increases in plasma levels of calcitonin and serum levels of tryptase paralleled those of calcitonin gene-related peptide, but plasma levels of calcitonin remained increased for up to 18 hours. Urinary excretion of histamine and 1-methyl-4-imidazoleacetic acid also showed precipitous, although delayed, increases. Excretion of the prostaglandin D2 metabolite 11 beta-prostaglandin F2 alpha followed a bimodal pattern during aspirin desensitization; after severe hypotensive responses, the maximal value was more than 490,000 pg/mL, but the level decreased to less than 100 pg/mL after therapeutic serum levels of salicylate were attained.

CONCLUSION

These data suggest that the hypotensive responses to aspirin in some patients with systemic mast cell disease may result from the combined effects of several mediators.

Increased plasma calcitonin levels in systemic mast cell disease

Aspirin therapy for patients with systemic mast cell disease (SMCD) decreases the production of prostaglandin D2, which is thought to be a major mediator of flushing. Paradoxically, in 5 to 10% of patients with SMCD, administration of aspirin causes massive mediator release and an anaphylactoid reaction. We attempted aspirin desensitization in a 34-year-old man with SMCD (confirmed by bone marrow biopsy) who was incapacitated by severe flushing episodes and hypotension. His baseline mediator levels of plasma calcitonin, urinary histamine, and urinary N-methyl-imidazoleacetic acid were abnormal. Pentagastrin stimulation increased the plasma level of calcitonin from 47 pg/mL to 130 pg/mL (normal, less than or equal to 110) at 5 minutes. Oral aspirin desensitization was begun; however, after a cumulative dose of 620 mg, an anaphylactoid reaction ensued in conjunction with hypotension, abdominal cramping, and flushing. Coincidentally, 1 hour after the episode, the plasma calcitonin level increased from 37 pg/mL to 540 pg/mL, and the serum tryptase level increased from 1 ng/mL to 3.9 ng/mL. Six hours after the episode, the urine level of histamine increased from 90 micrograms/g creatinine to 337 micrograms/g creatinine, and the urinary N-methylimidazoleacetic acid increased from 32 mg/24 h to 81 mg/24 h. Hence, the patient had increased basal levels of plasma calcitonin that increased substantially during aspirin desensitization and increased to above the upper limit of normal during pentagastrin stimulation. Human mast cells may be capable of producing calcitonin or causing secretion of calcitonin in response to skeletal changes.

Mastocytosis: a review

Mastocytosis refers to a spectrum of clinical and laboratory abnormalities attributable to tissue infiltration by large numbers of mast cells and to the discharge of various biologically active substances by these cells. It most commonly results in cutaneous manifestations during childhood but may develop at any age or involve almost any organ system. The treatment of mastocytosis has become considerably more practicable in recent years with the availability of agents that directly inhibit mast cells or temporarily reduce their quantity in the skin.