Ryusuke Saito

Inner Ear Anomalies in Dogs

Congenital deafness in dogs has been known for a long time and inner ear anomalies have been previously documented in different kinds of dogs: in the white Bull-Terrier,l in the Dalmatian,*-5 and in the Collie.* Cochleosaccular degeneration was found exclusively in these reports. In the present study, by utilizing serial temporal bone sections, inner ear end organs in four different species of dogs were studied in order to investigate the developmental pathology in the different structures of the inner ear apparatus among these species.

SINUS HISTIOCYTOSIS WITH MASSIVE LYMPHADENOPATHY IN A JAPANESE ADULT WITH UNUSUALLY ELEVATED EBV ANTIBODY TITERS

A 35‐year‐old Japanese male was presented with massive lymphadenopathy in bilateral preauricular and submandibular regions for five years’duration without any complaints despite of no specific treatments. Laboatory examinations revealed neutrophilia, elevated BSR, hypergammaglobulinemia with elevated IgG and IgM, positive CRP and RA, low percentage of T‐cells in peripheral blood, impaired PHA blast transformation, and elevated EBV titers against viral capsid, early and nuclear antigens. Biopsy specimens demonstrated massive histiocytosis with hemophagocytosis in the sinuses and predominant mature plasma cells in the medulla, which were fairly well consistent with “sinus histiocytosis with massive lymphadenopathy” (Rosai and Dorfman). Ultrastructural study revealed histiocytes exhibiting avid phagocytosis of blood cells, epithelioid histiocytes with poor phagocytic activity, foamy storage histiocytes loaded with a large number of osmiophilic lipid granules and giant cells of various types. Pathogenesis of this apparently benign disease entity was briefly discussed, and its refractoriness against any specific therapy was emphasized.

FIBROUS HISTIOCYTOMA OF THE NASAL CAVITY AND MAXILLARY SINUS

Two cases of fibrous histiocytoma were presented; Case 1: a 46‐year‐old man with a tumor filling the left nasal cavity and maxillary sinus, and Case 2: an 80‐year‐old man with a tumor of the right maxillary sinus destroying its surrounding wall. Histologically, the former was dominated by storiform pattern and onion‐like structures, and the latter by osteoclast‐like multinucleated giant cells. After radical surgery, Case 1 was free of recurrence for more than one year, and Case 2 showed recurrence although still maintaining fairly good health. A total of 29 cases hitherto reported arising in the nasal, paranasal and nasopharyngeal regions were reviewed, pitfall of differential diagnoses was commented especially in our two cases, criteria of malignancy were discussed, and the necessity of repeated samplings was emphasized because of paucity and unfamiliarity of fibrous histiocytoma arising, in particular, from the upper respiratory tract.

False-positive magnetic resonance image in the diagnosis of small acoustic neuroma

A patient presented with sudden hearing loss on her first visit to our department. Gadolinium-DTPA-enhanced magnetic resonance imaging (MRI) of the posterior cranial fossa portrayed an intracanalicular tumour image (2-3 mm), and the pure tone average (PTA) and speech discrimination score (SDS) values were 65 dB and 60 per cent, respectively. Surgical intervention to remove the suspected tumour was scheduled by the translabyrinthine approach. Intracanalicular observations by the retrolabyrinthine approach revealed limited oedema on the inferior vestibular nerve with vascular dilation. The tumour image disappeared two years after the operation. Surgical findings and the post-operative course advocate that gadolinium-DTPA-enriched MRI image of an intracanalicular lesion such as arachnoiditis might produce a false-positive result.

Temporal Bone Pathology of Metastatic T-Cell Lymphoma

Metastatic lymphoma involving the temporal bone is a rare tumour. A review of the English literature revealed only 13 reported cases. The common metastatic sites within the temporal bone are bone marrow and the internal auditory canal (IAC). Non-Hodgkin lymphoma has a tendency to infiltrate to the inner ear and middle ear, with bone marrow involvement. Recent advances in immunology have redefined the malignant lymphoma as a neoplasm of the immune system that has involved T and B cells. We present a case of non-Hodgkin T-cell lymphoma that metastasized to the temporal bone and central nervous system.

Minimally Invasive Procedure for Accurate Diagnosis of Mucosa-associated Lymphoid Tissue Lymphoma of the Head and Neck

Sonography-guided cutting needle biopsy for the diagnosis of malignant lymphoma has recently come into wide use. However, surgery is sometimes unavoidable for the diagnosis of malignant lymphoma, particularly for low-grade malignant lymphoma such as extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue, because cutting needle biopsy offers limited diagnostic accuracy for low-grade malignant lymphoma. Of course, unnecessary invasive procedures like open biopsy should be avoided wherever possible, given the cosmetic problems and burden on the patient. We tried to diagnose malignant lymphoma using the combination of cutting needle biopsy, flow cytometry and polymerase chain reaction to identify monoclonal rearrangement of immunoglobulin heavy chain genes. We have used this method in two cases in whom malignant lymphoma was suspected in the head and neck region, allowing diagnosis of mucosa-associated lymphoid tissue lymphoma in both cases. One case involved a 23-year-old woman with mucosa-associated lymphoid tissue lymphoma in the parotid glands, and the other involved a 77-year-old man with mucosa-associated lymphoid tissue lymphoma in the thyroid. The combination of cutting needle biopsy, flow cytometry and immunoglobulin heavy chain gene rearrangement testing might offer a useful alternative to open biopsy for the diagnosis of mucosa-associated lymphoid tissue lymphoma. We recommend this procedure, particularly for young women or patients with poor performance status in whom malignant lymphoma is suspected.

Temporal Bone Pathology in Congenital Anomalies of the Oval Window and the Facial Nerve

Temporal bones of six infants with congenital ear anomalies were examined for abnormalities of the oval window and facial nerve. These temporal bones were classified into two groups according to the degree of malformation: group A, those with atresia or absence of the oval window; and, group B, those with hypoplasia of the stapes and annular ligament. Group A, consisting of five ears, were associated with severe middle ear anomalies such as the abnormal course of the facial nerve and absence of the stapes. In group B, consisting of seven ears, the stapes were present and the facial nerve presented minor anomalies such as obtuse angulation at the first genu, central migration of the geniculate ganglion cells, ectopic muscles and a wide bony dehiscence of the facial canal around the oval window. Probable origin of the anomalies in group A could mainly be due to maldevelopment of the facial nerve during an earlier embryonal period while that of group B could have developed after the ninth week of the fetal period and are mostly localized along the second branchial arch.

Epithelial hyperplasia of the larynx a clinical follow-up study

In this retrospective study, the records of 40 patients with epithelial hyperplasia of the larynx, seen between 1980-1991, were reviewed to determine the incidence of malignant transformation during long term follow-up. The mean follow-up time was 58.6 months. The initial pathological diagnoses were hyperkeratosis in one case, parakeratosis in one, dyskeratosis in 12 and dysplasia in 26. During follow up, nine patients developed carcinoma in situ and/or invasive carcinoma. Of these, two patients had been diagnosed with dyskeratosis without dysplastic cells at the initial biopsy. It is therefore important to follow up patients with epithelial hyperplasia of the larynx even when no dysplastic cells are found at the time of diagnosis.

Vascular Anatomy of the Inner Ear of The Guinea Pig: —A Sem Study Of The Corrosion Cast—

This paper shows a casting method of the vascular system of the inner ear of the guinea pig with the use of fluid resin injected intravascularly and the observation of those specimens by means of the scanning electron microscopy. First, fluid resin was injected into the blood vessels of a live or just sacrificed guinea pig. After taking the temporal bone out of the animal, it was decalcified and macerated completely. Then, a cast of the inner ear vessels was taken and observed with a scanning electron microscope. A pair of photos differing in teh view angle by seven degrees were taken simultaneously, and observed with a stereoviewer. This technique brought photographs of well magnified three-dimensional construction of the inner ear blood vessels.

Temporal bone histopathology of atresia auris congenita with chromosome aberration.

Temporal bone findings in two infants demonstrating congenital aural atresia with microtia were presented focusing mainly on the external and middle ears. These two cases were proved to have chromosome aberration that is, 13-15 trisomy and extra chromosome in group G individually. Temporal bones showed the multiple anomalies through the external, middle and internal ears. The external canals were filled with connective tissue in one case and with bony plate in the other to form aural atresia. There were no development of the tubotympanic recess in a case of 13-15 trisomy. The oval window area in both cases was poorly developed resulting in a connective tissue fissure in the lateral wall of the vestibule except for one ear, while the round windows were normally formed in all ears. The facial nerves showed an abnormal running course without forming the geniculate ganglion and the horizontal segment. These findings indicate that the structures derived from the second branchial arch might be more deeply involved than the first one in the congenital aural atresia.