Orbital rosai-dorfman disease in a five-year-old boy.

Rosai-Dorfman disease (RDD) is characterized by histiocytic proliferation and massive cervical lymphadenopathy, although some patients have extra-nodal involvement. We report a case of extranodal RDD in a five-year-old child, initially misdiagnosed as orbital inflammatory disease and treated with oral steroids. A subsequent orbital biopsy three years later confirmed the diagnosis of Rosai Dorfman disease.

Parotid tumor presenting with hemifacial spasm.

A 47-year-old man presented with right parotid swelling and a history of frequent attacks of hemifacial spasm. MRI of the brain and neck showed a mass in the right parotid gland. Fine needle aspiration biopsy of the mass revealed a pleomorphic adenoma of the parotid gland, which was confirmed after total right parotidectomy. His attacks of hemifacial spasm did not improve after surgery and 8 months postoperatively, he received botulinum toxin-A injections, which improved his symptoms. Clinicians need to be aware that patients with occult parotid tumors can present like patients with classic hemifacial spasm.

Differences in Ototoxicity across Species.

OBJECTIVE: To illustrate some differences between humans and rodents in the dose-effect relationships for two ototoxic drugs. STUDY DESIGN: Controlled animal study using typical research regimens for gentamicin and cisplatin compared with human data from the clinical literature. METHODS: Auditory brainstem response testing was carried out over months in two groups of animals exposed to typical dose regimens for ototoxic drugs. In the first group, 30 guinea pigs received either 3 or 6 mg/kg of cisplatin on alternate days for 5 days (total dose 15 or 30 mg/kg). In the second group, 24 C57 mice received saline or 19 daily doses of gentamicin 120 mg/kg. The findings in rodents were contrasted with human toxicity in the literature. RESULTS: Cisplatin increased click thresholds (32 +/- 27 dB) in guinea pigs. Doses of 15 mg/kg caused less hearing loss than 30 mg/kg, but the higher dose was associated with greater mortality owing to renal insufficiency. These findings are comparable with expectations of similar doses of cisplatin in humans. In contrast, gentamicin produced less hearing loss in mice, although the dose employed was well above the lethal dose for humans. CONCLUSIONS: Ototoxic doses of cisplatin in guinea pigs are similar to those of humans, but C57 mice appear to be highly resistant to gentamicin-induced hearing loss compared to humans. Animal models of ototoxicity need to be considered carefully in translational research.

Assessment of the protective effects of amifostine against cisplatin-induced toxicity.

OBJECTIVE: The goals of this study were to determine whether the toxicity of cisplatin, a chemotherapeutic alkylating agent, could be reduced by the use of amifostine and to determine whether amifostine alone could cause ototoxicity. STUDY DESIGN: Prospective, animal study. METHODS: Auditory brainstem response click threshold, latencies, and blood work were used to measure ototoxicity, nephrotoxicity, and myelotoxicity before and 4 weeks after treatment. Groups of guinea pigs received either cisplatin alone (30 mg/kg), amifostine (1000 mg/kg), cisplatin plus amifostine (1000 mg/kg), or no agent. RESULTS: Amifostine reduced the hearing loss caused by cisplatin for many animals. Amifostine partially protected against cisplatin-induced ototoxicity and renal toxicity. We did not find evidence for myelotoxicity owing to cisplatin in this sample. CONCLUSION: Amifostine may have a role in reducing toxicity or permitting larger doses of cisplatin to be given, but toxicity can still be significant even with protection.