Person:

Holbrook, Eric

Background and Importance Plasmacytomas are monoclonal proliferations of plasma cells that may arise within soft tissue or bone. The skull base is a rare site for plasmacytomas to occur, and few cases have been reported in the literature. When present in the skull base, plasmacytomas may result in cranial neuropathies and often progress to multiple myeloma more rapidly than other intracranial or skeletal plasmacytomas. Clinical Presentation A 69-year-old man presented with a primary complaint of diplopia and an examination consistent with bilateral abducens nerve palsy. No other deficits were noted. Magnetic resonance imaging of the skull base demonstrated a large T1 isointense moderately enhancing lesion centered within the clivus. Endoscopic biopsy of the mass revealed sheets and aggregates of mature monoclonal plasma cells. The patient's initial systemic work-up revealed that this was a solitary lesion, and he was treated with radiation therapy to the skull base with a durable local effect at 18-month follow-up. Unfortunately he progressed to multiple myeloma with peripheral osteolytic lesions but has been stabilized on chemotherapeutics. Conclusion: The clivus is an unusual site for intracranial plasmacytomas, and enhancing lesions must be differentiated from chordoma. Characteristic findings on histopathology include an immunoglobulin light-chain restricted clonal proliferation of plasma cells. Treatment is most commonly radiotherapy with surgery reserved for biopsy and palliation. Clinicians should be aware of the increased risk of progression to multiple myeloma in skull base plasmacytomas.

Background: Sphenoid sinus fungal balls (SSFB) are rare entities that can result in serious orbital and intracranial complications. There are few published reports of complications that result from SSFB. Objective: To review the incidence of skull base erosion and orbital or intracranial complications in patients who present with SSFB. Methods: A retrospective review was performed of all the patients with SSFB who were treated at the Massachusetts Eye and Ear Infirmary from 2006 to 2014. Presenting clinical data, radiology, operative reports, pathology, and postoperative course were reviewed. Results: Forty-three patients with SSFB were identified. Demographic data were compared between patients with (39.5%) and those without (61.5%) skull base erosion. Two patients underwent emergent surgery for acute complications of SSFB (one patient with blindness, one patient who had a seizure). Both patients with acute complications had evidence of skull base erosion, whereas no patients with an intact skull base developed an orbital or intracranial complication (p = 0.15). All the patients were surgically managed via an endoscopic approach. Conclusion: SSFBs are rare but may cause significant skull base erosion and potentially severe orbital and intracranial complications if not treated appropriately. Endoscopic sphenoidotomy is effective in treating SSFB and should be performed emergently in patients who presented with associated complications.

Background: The progression from a benign pigmented lesion on the skin to cutaneous melanoma is better understood, and it could be presumed that a similar progression occurs with mucosal lesions. However, to our knowledge, there has never been documentation of melanosis transforming into melanoma over time. Objective: To describe a transformation of a mucosal melanosis into melanoma. Methods: A 53-year-old man with diffuse melanosis of the nasal cavity underwent surgical resection. Results: Pathology revealed melanocytic hyperplasia without evidence of melanoma. The patient was serially examined, with excisions for new areas of melanosis. The pathology progressed to severely atypical melanocytic proliferation and melanoma in situ over a 4-year period. Conclusion: Nasal melanosis may be a precancerous lesion and may transform into melanoma. All melanosis should be biopsied with close endoscopic observation. Lesions with dysplasia or atypia should be excised due to potential transformation to melanoma.

Objectives To characterize the temporal distribution and resolution rate of postoperative complications from endoscopic skull base surgery.

Design Retrospective review of patients undergoing endoscopic resection of paranasal sinus or skull base neoplasm from 2007 to 2013.

Setting Massachusetts General Hospital/Massachusetts Eye and Ear Infirmary Cranial Base Center.

Participants Fifty-eight consecutive patients.

Main Outcome Measures Postoperative complications were categorized as cerebrospinal fluid (CSF) leak, pituitary, orbital, intracranial, or sinonasal. Complications were temporally categorized as “perioperative” (within 1 week), “early” (after 1 week and within 6 months), or “delayed” (after 6 months).

Results The most common perioperative complications were diabetes insipidus (19.0%), CSF leak (5.2%), and meningitis (5.2%), with resolution rates of 75%, 100%, and 100%, respectively. Overall, CSF leak occurred in 13.8% of patients and resolved in all cases. A total of 53.8% of all complications were evident within 1 week of surgery. Chronic rhinosinusitis was the most common delayed complication (3.4%). Hypopituitarism and delayed complications were less likely to resolve (p = 0.014 and p = 0.080, respectively).

Conclusions Monitoring of complications after endoscopic skull base surgery should focus on neurologic complications and CSF leak in the early postoperative period and development of chronic rhinosinusitis in the long term. Late-onset complications and hypopituitarism are less likely to resolve.

Emerging evidence points to proteoglycans abnormalities in the pathophysiology of schizophrenia (SZ). In particular, markedly abnormal expression of chondroitin sulfate proteoglycans (CSPGs), key components of the extracellular matrix, was observed in the medial temporal lobe. CSPG functions, including regulation of neuronal differentiation and migration, are highly relevant to the pathophysiology of SZ. CSPGs may exert similar functions in the olfactory epithelium (OE), a continuously regenerating neural tissue that shows cell and molecular abnormalities in SZ. We tested the hypothesis that CSPG expression in OE may be altered in SZ. CSPG-positive cells in postmortem OE from nonpsychiatric control (n=9) and SZ (n=10) subjects were counted using computer-assisted light microscopy. ‘Cytoplasmic’ CSPG (c-CSPG) labeling was detected in sustentacular cells and some olfactory receptor neurons (c-CSPG+ORNs), while ‘pericellular’ CSPG (p-CSPG) labeling was found in basal cells and some ORNs (p-CSPG+ORNs). Dual labeling for CSPG and markers for mature and immature ORNs suggests that c-CSPG+ORNs correspond to mature ORNs, and p-CSPG+ORNs to immature ORNs. Previous studies in the same cohort demonstrated that densities of mature ORNs were unaltered (Arnold et al, 2001). In the present study, numerical densities of c-CSPG+ORNs were significantly decreased in SZ (p <0.025; 99.32% decrease), suggesting a reduction of CSPG expression in mature ORNs. Previous studies showed a striking increase in the ratios of immature neurons with respect to basal cells. In this study, we find that the ratio of p-CSPG+ORNs/ CSPG+ basal cells was significantly increased (p=0.03) in SZ, while numerical density changes of p-CSPG+ORNs (110.71% increase) or CSPG+ basal cells (53.71% decrease), did not reach statistical significance. Together, these results indicate that CSPG abnormalities are present in the OE of SZ and specifically point to a reduction of CSPGs expression in mature ORNs in SZ. Given the role CSPG play in OE cell differentiation and axon guidance, we suggest that altered CSPG expression may contribute to ORN lineage dysregulation, and olfactory identification abnormalities, observed in SZ.

Tethered, flying Australian field crickets (Teleogryllus oceanicus) stimulated with ultrasound respond with a rapid, short-latency turn from the sound source. We analyzed the kinematics of two behavioral components of this acoustic startle response and recorded electromyograms from the muscles involved in producing them. The two behavior patterns studied were the swing of the metathoracic leg, which has been shown to elicit a short-latency turn, and a lateral swing of the antennae, for which a direct role in steering has not been demonstrated. The kinematic data showed that when a pulse of ultrasound was presented to one side of the animal (1) the contralateral metathoracic leg abducted and elevated, while the ipsilateral leg remained in place, (2) both antennae swung laterally, but the contralateral antenna moved farther than the ipsilateral antenna, (3) increases in stimulus intensity elicited larger movements of the leg and contralateral antenna, while the ipsilateral antenna showed little sensitivity to stimulus intensity, and (4) for the leg, the latency to the onset of the swing decreased and the duration of the movement increased with increasing stimulus intensity. Electromyograms were recorded from the leg abductor M126 and two antennal muscles: the medial scapo-pedicellar muscle M6 and the lateral scapo-pedicellar muscle M7. M7 moves the antenna laterally, M6 moves it medially. Upon stimulation with ultrasound (1) both M126 and M7 showed increasing spike activity with increasing intensity of the ultrasound stimulus, (2) M126 showed a decrease in latency to the first spike and an increase in the duration of spike activity with increasing stimulus intensity, (3) latencies for M6 and M7 were not correlated with stimulus intensity, but M7 had significantly shorter latencies than M6 and the contralateral M7 had significantly shorter latencies than the ipsilateral M7, and (4) the ipsilateral M126 spiked in response to ultrasound in 6 of the 10 animals tested. In these cases, however, latency to the first spike was substantially longer, and the spike frequency was lower than for the muscle's response to contralateral stimuli. We attempt to correlate these electromyogram data with the kinematic data and relate them to the relevance of the two behavior patterns to the execution of an escape response.

Organic foreign bodies of the skull base are an uncommon problem with the potential for serious morbidity that present complicated treatment dilemmas best managed by a multidisciplinary approach. A 58-year-old male presented to the emergency department with fevers and mental status changes and was found to have bacterial meningitis. Computed tomography of the sinuses revealed two adjacent defects of the ethmoid roof with associated soft tissue density concerning for an encephalocele. He had a remote history of a penetrating left maxilla injury with a stick 13 years earlier. An attempted endoscopic repair of the defects revealed a pulsating splinter of wood emanating from the ethmoid roof defect. Neurosurgery and infectious disease were consulted and several wood fragments were removed endoscopically from the intracranial space. The skull base defects were closed using a septal cartilage underlay and free mucosal overlay graft. The patient has done well in follow-up with no evidence of cerebrospinal fluid leak. Organic foreign bodies from skull base trauma can have a delayed presentation and require a multidisciplinary team approach. In the appropriate setting endoscopic removal is a minimally morbid option.

The olfactory epithelium contains neuronal progenitor cells capable of continuous neurogenesis and is a unique model for studying neural degeneration, regeneration, axon outgrowth and recovery from injury. Matrix metalloproteinases (MMPs), and tissue inhibitors of metalloproteinases (TIMPs), have been implicated in cell turnover, development, migration, and metastatic processes. We used Western blot and immunohistochemistry to determine whether MMP-2 and associated proteins TIMP-2 and membrane type 1 matrix metalloproteinase (MT1-MMP) are present in the olfactory epithelium of mice. We found MMP-2 expression localized to the olfactory basal cells and immature neurons. After injury-induced neural degeneration, MMP-2 and MT1-MMP levels decreased while TIMP-2 levels increased. However, following 35 days of neurogenesis and cell replacement TIMP-2 and MT1-MMP returned to control levels. The results show a correlation between MMP and TIMP levels and the stages of neural degeneration, regeneration and recovery of the olfactory epithelium following injury.

Objective

To develop an alternative model for studying the regenerative capacity of olfactory neurons.

Study Design

An immunohistochemical analysis of mouse olfactory epithelium transplanted to the cerebral cortex.

Methods

Strips of olfactory epithelium removed from donor mice at postnatal day 5 to day 20 were inserted into the parietal cortex of adult mice. Recipient animals were allowed to survive for 25 to 120 days and then perfused with 4% paraformaldehyde 1 hour after bromodeoxyuridine injection. The brains were processed, and frozen sections were obtained. Sections through transplant tissue were analyzed using immunohistochemistry and compared with normal olfactory epithelium.

Results

Graft survival approached 85% with mature olfactory neurons detected in 35% of the transplants stained for olfactory marker protein. Transplant epithelium resembled normal olfactory epithelium containing mature olfactory neurons and axon bundles.

Conclusions

Studies of olfactory neuron regeneration have been limited by the inability to produce cultures with long-term viability. Olfactory epithelial grafts to the cerebral cortex provide an alternative approach to the study of olfactory neuron regeneration.

Objectives/Hypothesis

The pathophysiology underlying human olfactory disorders is poorly understood because biopsying the olfactory epithelium (OE) can be unrepresentative and extensive immunohistochemical analysis is lacking. Autopsy tissue enriches our grasp of normal and abnormal olfactory immunohistology and guides the sampling of the OE by biopsy. Furthermore, a comparison of the molecular phenotype of olfactory epithelial cells between rodents and humans will improve our ability to correlate human histopathology with olfactory dysfunction.

Study Design

An immunohistochemical analysis of human olfactory tissue using a comprehensive battery of proven antibodies.

Methods

Human olfactory mucosa obtained from 21 autopsy specimens was analyzed with immunohistochemistry. The position and extent of olfactory mucosa was assayed by staining whole mounts with neuronal markers. Sections of the OE were analyzed with an extensive group of antibodies directed against cytoskeletal proteins and transcription factors, as were surgical specimens from an esthesioneuroblastoma.

Results

Neuron-rich epithelium is always found inferior to the cribriform plate, even at advanced age, despite the interruptions in the neuroepithelial sheet caused by patchy respiratory metaplasia. The pattern of immunostaining with our antibody panel identifies two distinct types of basal cell progenitors in human OE similar to rodents. The panel also clarifies the complex composition of the esthesioneuroblastoma.

Conclusion

The extent of human olfactory mucosa at autopsy can easily be delineated as a function of age and neurological disease. The similarities in human vs. rodent OE will enable us to translate knowledge from experimental animals to humans and will extend our understanding of human olfactory pathophysiology.