Idiopathic midline destructive disease: fact or fiction

The differential diagnosis of a progressive destructive lesion of the midface and upper airway region includes both neoplastic and non-neoplastic entities; of these, the majority of cases prove to be either Wegener's granulomatosis or lymphoma. Historically, these sorts of necrotizing midfacial lesions were diagnosed clinically, and as a consequence a variety of overlapping categories of disease sprang up. As pathologic examination of biopsy material became both more widespread and (particularly in the last several years) more sophisticated, many lesions previously thought to be of mysterious origins have proven to be examples of lymphoma (in particular, sinonasal natural killer cell or T cell [NK/T] lymphomas). At present, the evaluation of a patient with a progressive destructive process involving the midface region should include imaging studies (to delineate the extent of disease) as well as biopsy (with sampling of lesional tissue for application of sophisticated testing--including immunohistochemical studies, flow cytometry, or molecular studies as necessary--to exclude the possibility of a NK/T cell lymphoma). There remain occasional patients whose necrotizing midfacial lesions continue to be difficult to classify despite the application of extensive testing; such patients are sometimes described as suffering from the nebulous entity of "idiopathic midline destructive disease". While it remains to be seen whether such patients will ultimately be assigned to other diagnostic groups (as, for example, occult toxic injuries--as in the case of cocaine abusers who are not forthcoming with regard to their drug usage), it seems likely that "idiopathic midline destructive disease" is a diagnostic term of questionable validity which should be used only with extreme reticence in modern practice.     

Teratoma of the middle ear: a real entity or a non-entity?

Space-occupying lesions of the middle ear range from wholly benign developmental anomalies to highly virulent and aggressive malignancies. Amongst the benign entities classed with the family of developmental anomalies, the middle ear choristoma is well known. But what of the middle ear teratoma? Recent reports suggest that, while rare, teratomas of the middle ear do exist. Middle ear teratomas are defined as tumors consisting of benign tissues derived from all three embryologic layers: endoderm, mesoderm and ectoderm. They are lesions of the neonatal period and early infancy. While complete surgical excision will be curative, a thorough histologic examination of the specimen is recommended to exclude the possibility of immature and/or frankly malignant elements being admixed with the benign teratomatous elements.     

Merkel cell carcinoma of the auricle

Merkel cell carcinoma (MCC) is an uncommon cutaneous neoplasm which arises in adults with a peak incidence in the sixth and seventh decades. MCC most often arises in the head and neck area and extremities. Among head and neck primary sites, auricular MCC has proven to be rare and only 20 cases have been reported in the literature. Auricular MCC follows the same aggressive course as has been documented for MCC arising elsewhere: the tumor has a propensity for recurring locally and metastasizing to regional lymph nodes and distant sites. Location of MCC in the auricular regions does not appear to confer any survival advantage compared with MCC arising elsewhere. The mainstay of treatment is surgery, with attempts at complete surgical excision being of paramount importance. What role regional node dissection, radiation therapy and chemotherapy may play in the standard treatment of auricular MCC remains to be clearly established.     

Comparison of right ventricle to pulmonary artery conduit and modified Blalock-Taussig shunt hemodynamics after the Norwood operation

The Norwood procedure remains one of the highest-risk operations in congenital heart surgery. A significant contributor to this risk is thought to be the diastolic run-off into the modified Blalock-Taussig shunt (MBTS). In an effort to eliminate this risk, several groups have begun to utilize a right ventricle to pulmonary artery conduit (RVPAC), which decreases this diastolic “steal” of coronary blood flow. Whereas initial results with the RVPAC are encouraging, the postulated hemodynamic advantages are unproven. This case illustrates the positive hemodynamic changes by echocardiography after the replacement of a MBTS with a RVPAC in a patient after a Norwood procedure.     

Paragangliomas of the head and neck

Paragangliomas are neuroendocrine tumors derived from the extra-adrenal paraganglia of the autonomic nervous system. Within the head and neck, they are generally defined and named according to their site of origin, and may be found frequently neighboring vascular structures. Physiologic activity is rare in these neoplasms and they may exhibit patterns of inheritance which predispose their occurrence in families, often with multicentricity. These tumors generally exhibit a slow rate of growth, most often presenting asymptomatically as a space occupying mass lesion noted clinically or radiographically. The most common paraganglioma of the head and neck is the carotid body tumor followed by the jugulo-tympanic and vagal varieties. Other rare sites where this tumor may occur include; the larynx, sinonasal chambers and orbit. Diagnosis is generally made through a combination of clinical findings and radiographic studies. Magnetic resonance represents the most important imaging modality for the evaluation and characterization of suspected head and neck paraganglioma. Definitive management for these lesions should be carefully considered in relation to both tumor and patient-oriented factors, especially in regard to the potential morbidity of treatment. Surgery and radiation therapy represent the main treatment modalities for paraganglioma. The selection of treatment depends on the size, location, and biologic activity of the tumor as well as the overall fitness of the patient. Although radiotherapy may be effective in arresting growth of these tumors, rarely is the neoplasm eliminated without surgical resection. Surgery may be associated with significant morbidity, primarily as a consequence of incurring major cranial nerve injury. Patient selection (relative to age and medical condition) should be carefully considered prior to recommending aggressive surgery for paragangliomas of head and neck, especially in those patients at risk for disabling surgical morbidity.     

Infection with Brugia microfilariae induces apoptosis of CD4(+) T lymphocytes: a mechanism of immune unresponsiveness in filariasis

In humans infected with lymphatic filariasis, microfilaraemia [the presence of microfilariae (Mf) in the blood] is generally associated with both poor antigen (Ag)-specific proliferative responses and with protection from severe disease. Clonal deletion has been suggested as one possible mechanism by which parasite-reactive lymphocytes, that may be capable of mediating resistance and/or immunopathology, are silenced in asymptomatic carriers. In this study we demonstrate that splenic lymphocytes from mice infected with microfilariae of Brugia pahangi display an Ag-specific proliferative defect. However, these cells were not completely unresponsive since they produced high levels of Ag-specific IFN-gamma. Using TdT-mediated dUTP-biotin nick end labeling for flow cytometry, CD4(+) lymphocytes from Mf-infected mice cultured with Ag showed high levels of apoptosis when compared to those from L3-infected mice which proliferated well in response to Ag. Treatment of Ag-stimulated cultures with aminoguanidine (AMG), an inhibitor of inducible nitric oxide synthase, rescued the CD4(+) T cells from apoptosis and reversed the proliferative defect. Furthermore, carboxyfluorescein diacetate succinimidyl ester labeling allowed the visualization of dividing CD4(+) T cells in cultures from Mf-infected animals only in the presence of AMG. We hypothesize that CD4(+) T cells indirectly trigger their own apoptosis by secreting significant quantities of IFN-gamma resulting in the induction of high levels of nitric oxide, and the subsequent elimination of effector T cells. Our findings are the first direct evidence that infection with Brugia Mf can selectively induce lymphocyte apoptosis, a phenomenon that could contribute to the proliferative defect and parasite persistence associated with the microfilaraemic state in the infected human.