Genetic predisposition to peripheral nerve neoplasia: Diagnostic criteria and pathogenesis of neurofibromatoses, Carney complex, and related syndromes

Division of Neuropathology, Department of Pathology, Johns Hopkins University, 720 Rutland Avenue, Ross Building, 512B, Baltimore, MD 21205, USA.
Acta Neuropathologica (Impact Factor: 10.76). 12/2011; 123(3):349-67. DOI: 10.1007/s00401-011-0935-7
Source: PubMed


Neoplasms of the peripheral nerve sheath represent essential clinical manifestations of the syndromes known as the neurofibromatoses. Although involvement of multiple organ systems, including skin, central nervous system, and skeleton, may also be conspicuous, peripheral nerve neoplasia is often the most important and frequent cause of morbidity in these patients. Clinical characteristics of neurofibromatosis type 1 (NF1) and neurofibromatosis type 2 (NF2) have been extensively described and studied during the last century, and the identification of mutations in the NF1 and NF2 genes by contemporary molecular techniques have created a separate multidisciplinary field in genetic medicine. In schwannomatosis, the most recent addition to the neurofibromatosis group, peripheral nervous system involvement is the exclusive (or almost exclusive) clinical manifestation. Although the majority of cases of schwannomatosis are sporadic, approximately one-third occur in families and a subset of these has recently been associated with germline mutations in the tumor suppressor gene SMARCB1/INI1. Other curious syndromes that involve the peripheral nervous system are associated with predominant endocrine manifestations, and include Carney complex and MEN2b, secondary to inactivating mutations in the PRKAR1A gene in a subset, and activating mutations in RET, respectively. In this review, we provide a concise update on the diagnostic criteria, pathology and molecular pathogenesis of these enigmatic syndromes in relation to peripheral nerve sheath neoplasia.

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    • "Early detection for cardiac myxomas using echocardiography is essential, as these tumors can lead to sudden death by embolism, stroke or cardiac failure. Cardiac myxomas are the most common, clinically significant non-cutaneous lesions in patients with CNC [15]. The mean age of patients with myxomas is 26 years old, and 62% of patients are women. "
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    ABSTRACT: Carney complex is an autosomal dominant syndrome with multiple neoplasms in different sites, including myxomas, endocrine tumors and lentigines lesions. To the best of our knowledge, this is the first report of Carney complex presenting with a unilateral adrenal adenoma associated with a pituitary incidentaloma. A 27-year-old Iranian woman was referred to our endocrinology clinic with amenorrhea and hirsutism, further confirming a diagnosis of adrenocorticotropic hormone-independent Cushing's syndrome. The cause was believed to be a right adrenocortical adenoma based on a computed tomography scan. Our patient underwent a right laparoscopic adrenalectomy and pathological examination revealed pigmented micronodular adrenal hyperplasia. Pituitary magnetic resonance imaging also documented a microadenoma that was considered to be an incidentaloma based on normal pituitary function tests. Recurrence of hypercortisolism led to a left laparoscopic adrenalectomy, providing further evidence for the diagnosis of primary pigmented nodular adrenocortical disease. Carney complex was established in light of her history of cardiac myxomas. We present what we believe to be the first case of Carney complex presenting with a unilateral adrenocortical adenoma in association with a pituitary incidentaloma. Although primary pigmented nodular adrenocortical disease is rare as a component of Carney complex, it should be considered in the differential diagnosis of Cushing's syndrome. Rarely, adrenal and pituitary imaging can be misleading.
    Journal of Medical Case Reports 02/2014; 8(1):38. DOI:10.1186/1752-1947-8-38
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    ABSTRACT: Peripheral nerve sheath tumors are common neoplasms, with classic identifiable features, but on occasion, they are diagnostically challenging. Although well-defined subtypes of peripheral nerve sheath tumors were described early in the history of surgical pathology, controversies regarding the classification and grading of these tumors persist. Advances in molecular biology have provided new insights into the nature of the various peripheral nerve sheath tumors, and have begun to suggest novel targeted therapeutic approaches. In this review, we discuss current concepts and problematic areas in the pathology of peripheral nerve sheath tumors. Diagnostic criteria and differential diagnosis for the major categories of nerve sheath tumors are proposed, including neurofibroma, schwannoma, and perineurioma. Diagnostically challenging variants, including plexiform, cellular and melanotic schwannomas are highlighted. A subset of these affects the childhood population, and has historically been interpreted as malignant, although current evidence and outcome data suggest they represent benign entities. The growing current literature and the author's experience with difficult to classify borderline or "hybrid tumors" are discussed and illustrated. Some of these classification gray zones occur with frequency in the gastrointestinal tract, an anatomical compartment that must always be entertained when examining these neoplasms. Other growing recent areas of interest include the heterogeneous group of pseudoneoplastic lesions involving peripheral nerve composed of mature adipose tissue and/or skeletal muscle, such as the enigmatic neuromuscular choristoma. Malignant peripheral nerve sheath tumors (MPNST) represent a diagnostically controversial group; difficulties in grading and guidelines to separate "atypical neurofibroma" from MPNST are provided. There is an increasing literature of MPNST mimics which neuropathologists must be aware of, including synovial sarcoma and ossifying fibromyxoid tumor. Finally, we discuss entities that are lacking from the section on cranial and paraspinal nerves in the current WHO classification, and that may warrant inclusion in future classifications. In summary, although the diagnosis and classification of most conventional peripheral nerve sheath tumors are relatively straightforward for the experienced observer, yet borderline and difficult-to-classify neoplasms continue to be problematic. In the current review, we attempt to provide some useful guidelines for the surgical neuropathologist to help navigate these persistent, challenging problems.
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