Incidence of Fatal Anaphylaxis: A Systematic Review of Observational Studies.

BACKGROUND: Fatal anaphylaxis is very rare, with an incidence ranging from 0.5 to 1 deaths per million person-years. OBJECTIVE: Based on a systematic review, we aimed to explain differences in the reported incidence of fatal anaphylaxis based on the methodological and demographic factors addressed in the various studies. METHODS: We searched PubMed/MEDLINE, EMBASE, and the Web of Science for relevant retrospective and prospective cohort studies and registry studies that had assessed the anaphylaxis mortality rate for the population of a country or for an administrative region. The research strategy was based on combining the term "anaphylaxis" with "death", "study design", and "main outcomes" (incidence). RESULTS: A total of 46 studies met the study criteria and included 16,541 deaths. The range of the anaphylaxis mortality rate for all causes of anaphylaxis was 0.002-2.51 deaths per million person-years. Fatal anaphylaxis due to food (range 0.002-0.29) was rarer than deaths due to drugs (range 0.004-0.56) or Hymenoptera venom (range 0.02-0.61). The frequency of deaths due to anaphylaxis by drugs increased during the study period (IRR per year, 1.02; 95%CI, 1.00-1.04). We detected considerable heterogeneity in almost all of the meta-analyses carried out. CONCLUSION: The incidence of fatal anaphylaxis is very low and differs according to the various subgroups analyzed. The studies were very heterogeneous. Fatal anaphylaxis due to food seems to be less common than fatal anaphylaxis due to drugs or Hymenoptera venom.

Association Between Severity of Anaphylaxis and Co-occurrence of Respiratory Diseases: A Systematic Review and Meta-analysis of Observational Studies.

BACKGROUND AND OBJECTIVE: Asthma is very prevalent in all grades of severity of anaphylaxis. Asthma and chronic obstructive pulmonary disease (COPD) have been associated with the severity of anaphylaxis. Objective: We carried out a systematic review and meta-analysis to assess the influence of respiratory diseases on the severity of anaphylaxis. METHODS: We searched PubMed/MEDLINE, EMBASE, and the Web of Science for observational studies. The target studies were those that compared the severity of anaphylaxis between patients who had or did not have respiratory diseases. RESULTS: A total of 13 studies assessed the severity of anaphylaxis in respiratory disease. Respiratory disease increased the severity of anaphylaxis (OR, 1.87; 95%CI, 1.30-2.70), as did asthma (OR, 1.89; 95%CI, 1.26-2.83). For the meta-analysis of all studies (adjusted and nonadjusted), COPD increased the severity of anaphylaxis (OR, 2.47; 95%CI, 1.46-4.18). In the case of asthma studies, only 1 study assessed the influence of severity of asthma on severity of anaphylaxis. CONCLUSIONS: Evidence showing that respiratory disease increases the severity of anaphylaxis is low to moderate, although studies do not usually assess the importance of severity of asthma.

Seminal vesicle epithelium as a potential pitfall in the cytodiagnosis of presacral masses. A report of two cases.

BACKGROUND: Whenever abdominoperineal resection is performed because of a rectal adenocarcinoma, the prostate and seminal vesicles may be displaced backward to the presacral space, giving rise to a false radiologic image of a presacral tumor. Due to cytologic atypia associated with the epithelium of seminal vesicles, there is a real possibility, in fine needle aspiration biopsy (FNAB), of erroneously giving a malignant diagnosis. CASES: Two men, aged 53 and 57 years, presented with presacral masses three months and six years, respectively, after abdominoperineal resection for rectal adenocarcinoma. In both cases, FNAB smears showed some groups and single cells with large and irregular nuclei. These cells suggested a recurrence of carcinoma. The presence of cytoplasmic coarse pigment and a background with spermatozoa and blobs of inspissated secretory product were sufficient to determine that these presacral masses represented the seminal vesicles. CONCLUSION: Awareness that seminal vesicles may give rise to a radiologic impression of presacral tumor after abdominoperineal resection of the rectum will avoid unnecessary FNAB and a cytologic false positive diagnosis of colorectal adenocarcinoma.

Hepatic metastases from the spindle cell variant of medullary thyroid carcinoma: report of a case with diagnosis by fine needle aspiration biopsy.

BACKGROUND: The liver is a common site of neuroendocrine tumors (NTs) metastatic from primaries in the gastrointestinal tract, pancreas, biliary system and lungs. Medullary thyroid carcinoma (MTC) is also a potential source of metastases of NTs. Their metastases to the liver are frequent and can appear several years after the primitive tumor. Although a wide variety of cytomorphologic features are normally exhibited by MTC in smears, a spindle-shaped cell pattern can predominate, complicating the correct interpretation of a metastasis. CASE: A 63-year-old man presented with multiple liver nodules two years after a total thyroidectomy for MTC. Fine needle aspiration biopsy smears of the liver revealed neoplastic cells occurring in loose groupings or lying singly, most of them with a spindle shape and elongated nucleus with the characteristic "salt and pepper" chromatin pattern of a neuroendocrine tumor. Cytoplasmic dendritic processes and intranuclear inclusions were frequently seen. The cytomorphologic features of the tumor were essentially the same as those of the primary MTC. Immunoreactivity for calcitonin confirmed the diagnosis. CONCLUSION: In fine needle aspiration biopsy of liver masses, knowledge of the spindle pattern of the NT is important in order to achieve a correct diagnosis when metastases are the first manifestation of an occult primary tumor. Among neuroendocrine tumors, MTC must be included in the differential diagnosis.