Melanotic neuroectodermal tumor of infancy (MNT1) arising in the skull. Short review of two cases.

INTRODUCTION: Melanotic neuroectodermal tumor of infancy (MNT1) is a rare congenital pigmented neoplasm of neural crest origin, locally aggressive, and rapidly growing that develops during the first year of life. It most commonly arises from the maxilla, the cranial vault, and the mandible. Early diagnosis and radical surgery are critical for a long-term outcome. METHODS: A literature search through PUBMED revealed 43 cases of MNT1 arising in the skull. We reviewed the available literature and studied the presenting symptoms, diagnostic procedures, treatment, rates of recurrences, malignancy, and data of follow-up. We report two further cases of infants aged 4 and 10 months, respectively, with MNT1 arising from the cranial vault who underwent radical excision of the lesion. CONCLUSION: Melanotic neuroectodermal tumor of infancy should be included in the differential diagnosis of skull lesions in infants. Radical surgery must be considered as the treatment of choice and close follow-up for at least 2 years is necessary.

Low-Grade Papillary Schneiderian Carcinoma of the Sinonasal Cavity and Temporal Bone.

OBJECTIVES:: The aim of this study was to further characterize a newly described neoplasm, low-grade papillary Schneiderian carcinoma, occurring simultaneously in the sinonasal cavity and mastoid. Additionally, the authors review the only 2 similar cases within the literature and describe the common clinical features, radiographic findings, and pathologic characteristics of this exceptionally rare disease process. METHODS:: Chart review for single patient, review of literature. RESULTS:: The patient presented with bilateral nasal obstruction. Computed tomography revealed a left sinonasal mass with skull base hyperostosis, and follow-up magnetic resonance imaging showed a concomitant olfactory groove meningioma. Examination showed a bilateral, completely obstructing sinonasal mass with skip areas, and biopsy confirmed inverted papilloma (human papilloma virus strains 16 and 18 indeterminate). The patient underwent bilateral endoscopic sinus surgery, left medial maxillectomy, and left partial nasopharyngectomy. Given her multifocal disease, she was advised that she would require additional excision, but was lost to follow up. One year later she developed acute left facial paralysis. Magnetic resonance imaging demonstrated an enhancing mass in the left mastoid with enhancement along the Eustachian tube in addition to her known recurrent sinonasal disease. Simultaneous endoscopic sinus surgery and mastoidectomy were performed. Polypoid tissue was removed from the nasopharynx, mesotympanum, epitympanum, and retrofacial air cells. Immunohistochemistry showed that cells stained positive for p63 and dermCK and negative for synaptophysin. Morphologically, cells were bland, without classic stromal invasion, retaining their smooth, cystic, and papillary features, despite their increased depth within the tissue. Upon further review and consultation with an outside pathologist, a diagnosis of low-grade papillary Schneiderian carcinoma was made. The patient was referred for radiation therapy and is disease free at 3-month follow-up, with return of her facial function. CONCLUSIONS:: This case represents the first report of concurrent low-grade papillary Schneiderian carcinoma of both the nasal cavity and mastoid. It emphasizes the importance of recognizing this new entity through pathologic analysis and suspecting it when the clinical course does not follow an expected pattern.

Growth factors and bone regeneration. Implications of barrier membranes.

Insufficient or absence of bone healing is a frequent problem within all surgical fields. This often necessitates treatment by autogenous bone grafting. Recently, two new techniques to promote bone healing were introduced, the osteopromotive membrane technique, and local delivery of growth-stimulatory factors, both with a high rate of success in preclinical experiments. The aims of the present series of investigations were to further develop the membrane barrier technique, both by itself as well as in combination with local delivery of growth factors, in animal experiments. During membrane-promoted bone formation, the membrane porosity was found to be of importance for the initial rate of bone formation as well as for the performance of the material in the tissue. In contrast, the final amount of bone was not affected. In a well-known bone healing model, the 5 mm in diameter 'critical size defect' at the rat mandibular ramus, the efficacy of rhBMP-2, rhTGF-beta 1 and rhFGF-2 to promote bone regeneration alone and in combination with barrier membranes was evaluated. Under both conditions, rhBMP-2 was found to be an efficient promoter of bone healing. rhFGF-2 had some stimulatory effect both with and without barrier membranes, whereas rhTGF-beta 1 was found to have a minor stimulatory effect by itself, but in combination with barrier membranes it was inhibitory. These observations were interpreted as being the result of an effect of the growth factors at different levels of the osteoblastic lineage; rhBMP-2 being an inducer of osteoblastic cells from stem cells, whereas rhTGF-beta 1 may primarily act on already committed cells. In contrast, rhFGF-2 may have stimulatory effect at different levels of the lineage. Based on the positive results obtained by the combination of rhBMP-2 and barrier membranes in the rat mandible, this combination was then applied to (i) rabbit radius defects; and (ii) a rat calvarial osteoneogenesis model. In the long bone model, membranes by themselves were insufficient to promote bone healing, but the combination resulted in complete regeneration. In the osteoneogenesis model, the combination of barrier membranes and rhBMP-2 resulted in a 100% increase in the final amount of achievable bone. In the last study, rhFGF-2 (no barrier membranes) was shown to enhance revitalization of autoclaved autogenous bone grafts, a procedure clinically used in craniofacial reconstruction mainly after tumor surgery. The combined use of rhBMP-2 and barrier membranes has great potential to be a useful treatment for improving bone healing and might be an alternative to bone grafting.

Audiovestibular evolution in a patient undergoing surgical resection of a temporal bone myxoma.

Primary myxoma in the head and neck region occurs mostly in the maxilla and mandible, and rarely in the temporal bone. A 32-year-old female patient with temporal bone myxoma manifested as acute vertigo, headache, and tinnitus on the right ear. Audiometry and auditory brainstem response revealed normal responses, bilaterally. Vestibular function test displayed spontaneous nystagmus beating toward the left side. Absent ice water caloric response was disclosed on the right ear, whereas vestibular evoked myogenic potential test showed normal responses, bilaterally. MRI scan demonstrated a well-enhanced mass at the anterior middle portion of the right temporal bone with intracranial extension. Tumor excision via craniotomy was performed, and the histopathological study confirmed as myxoma. One year after operation, follow-up audiovestibular function tests revealed normal responses, except for 23 dB conductive hearing loss on the right ear.

Management of the large cranial osteoma: experience with 13 adult patients.

BACKGROUND: Large osteomas are benign, slow-growing and rare neoplasms of the skull, which are usually asymptomatic but may need surgical resection. PATIENT AND METHODS: We reported a series of 13 adult patients who had large cranial osteomas and who underwent surgical treatment over a period of 5 years. All of the patients were male and the mean age was 21.8 years. FINDINGS: Craniectomy associated with cranioplasty was performed in 10 patients and drilling of the bone tumor was performed in 3 patients. Tumour regrowth was not observed in any patient. CONCLUSION: Although most of the cranial osteomas are asymptomatic, surgical treatment is indicated for large ones. Each patient must be individualized and the selection of the type of surgery depends on the shape and growth pattern of the osteoma.

Squamous cell carcinoma of the pterygopalatine fossa (retroantral space).

A patient developed sensory disturbance and pain in the distribution of the maxillary nerve several months after removal of a statedly benign cutaneous malar lesion. One year later, abducens palsy developed, and computed tomography showed a mass of the pterygopalatine fossa abutting on the superior nasopharynx. Results of examination and multiple biopsies of the nasopharynx were normal. Direct biopsy of the pterygopalatine fossa via a transmaxillary sinus approach revealed squamous cell carcinoma. Extension of malignancy from the adjacent nasopharynx (not detected on biopsy) or sphenoid sinus and perineural spread of an undiagnosed cutaneous squamous cell carcinoma along the maxillary nerve were considered as possibilities. The anatomy of the pterygopalatine fossa and its environs is reviewed with respect to clinical signs of second division trigeminal neuropathy, abducens palsy and diminished ipsilateral tearing.

[Osteoinduction and -reparation]. / Osteoinduktion und -reparation.

Traumata, diseases, developmental deformities, and tumor resections frequently cause bone defects and atrophies. In general, three different mechanisms exist by which bone restoration can be achieved: (1) osteogenesis initiated by vital, osteoblastic cells of autografts; (2) osteoconduction (or creeping substitution); and (3) osteoinduction. The latter mechanism means the differentiation of pluripotent, mesenchymal-type cells (located in a recipient bed with strong regenerative capacity) into cartilage- and bone-forming progenitor cells under the influence of inductive bone morphogenetic proteins (BMPs). Some BMPs are physiologically included in low concentrations as organic components in bone tissue. They can diffuse from demineralized bone implants into the recipient bed and induce a differentiation into new bone tissue. Nine different BMPs have been isolated, characterized, and cloned. Some of these possess inductive properties and can initiate new bone formation in muscle tissue or in bone defects. In the future recombinant BMPs will be available in unlimited quantities. This will lead to completely new therapeutic concepts in reconstructive bone surgery.