Primary central nervous system lymphomas in immunocompetent patients.

Primary Central nervous system lymphoma is a rare non-Hodgkin's tumor of the brain that has been traditionally found in patients with immunodeficiency syndromes. However, there are several immunocompetent patients that have also been reported with this neoplasm. In this group of patients, the mean age of diagnosis is around 60-year old, with a very slight predominance in women. Macroscopically, most of the tumors are unique and mainly located in the supratentorial region in the proximity of the cerebrospinal fluid circulation. The typical histological pattern is a perivascular distribution of tumor cells, within a network of reticulin fibers. Even though they are usually well defined masses, it is not rare to find tumor invasion beyond the macroscopic margin. Coagulative necrosis is not as common as in immunodeficiency-related cases. Immunohistochemistry has demonstrated that most of the tumor cells are B-lymphocytes and the electron microscopic findings do not differ from those reported in systemic non-Hodgkin's lymphomas. There are several histological classifications of these tumors, some of them with recent modifications to facilitate the analysis, but unfortunately, up now with a little or no clinical significance. The diagnosis is based on the histological study of the specimen obtained mainly through a Stereotactic biopsy. The treatment is based on a combination of chemotherapy followed by radiotherapy, but the mortality rate is still high.

Zygomatic-transmandibular approach for giant tumors of the infratemporal fossa and parapharyngeal space.

OBJECTIVE: The surgical anatomy of the infratemporal fossa and parapharyngeal space is often not properly understood by neurosurgeons, because these areas are more related to other medical disciplines. This article provides a detailed description of the infratemporal fossa and parapharyngeal space anatomy in cadaveric specimens and offers a neurosurgical perspective on a surgical approach that allows wide exposure and complete resection of giant tumors in this location. METHODS: Ten cadaveric specimens were prepared for anatomic study. Dissections were performed to emphasize the relationship between bone, muscles, and neurovascular structures and to simultaneously expose the middle cranial fossa, the infratemporal fossa, and the parapharyngeal space. Ten patients with giant lesions in these areas (with maximum tumor diameter >8 cm) were treated via this approach. RESULTS: The main obstacles to approaching the infratemporal fossa and the parapharyngeal space are the zygomatic arch, the parotid gland, the facial nerve, and the ascending ramus of the mandible. Thus, by combining a pterional-zygomatic craniotomy with transmandibular access, working up and down the parotid gland, the exposure is wider and safer. Among the 10 patients treated, tumors were totally resected in 7, subtotally resected in 2, and partially resected in 1. Morbidity was unremarkable, and, in 8 patients, clinical status improved dramatically. CONCLUSION: The zygomatic-transmandibular approach allows resection of giant lesions in the middle cranial base, when they are invading the infratemporal fossa and parapharyngeal space, with a low morbidity rate.

Lesions confined to the sphenoid ridge: differential diagnosis and surgical treatment.

Tumors confined to the sphenoid ridge with little or no extradiploic extension are very rare; we describe here five patients with these lesions. Three were females and two males, with an average age of 33.4 years; the clinical presentation included proptosis and facial deformity. The diagnoses were three meningiomas (one "en plaque," one globous, and one intraosseous) and two fibrous dysplasias (compact form). Although the radiological findings were similar, we could find some details to establish the differential diagnosis before the surgical procedure. All the lesions were totally removed without complications. In a follow-up period of 15 to 36 months none of the lesions has shown clinical or radiological evidence of recurrence. We discuss the pathophysiology of each case, and propose the pterional orbito-zygomatic approach as the best way to resect lesions in this location.

[A case of rabies encephalitis with long survival. Clinical pathological correlations]. / Un caso de encefalitis rábica de larga evolución. Correlación clínico patológica.

We present a case of a 22 year old male patient who developed a rabies encephalomyelitis with evolution of six weeks, treated first as a psychiatric disorder and later as an encephalitis. This case had the following important features; 1--A long time with the disease: usually the patients die into the first eight days after diagnosis; 2--The evident reactive gliosis; 3--Almost all the studied fields showed inclusion bodies in both supratentorial and infratentorial portions; 4--The hippocampus and spinal cord neurons had many or unique Negri bodies and some of those were giant; 5--Microglia proliferation and free acidophilus bodies. All those microscopic features mean a long evolution time that is rarely seen in this illness; in medical literature we found only ten long duration cases.

[120 biopsies of pituitary adenomas studied by immunohistochemistry and electron microscopy. A clinico-pathological correlation]. / Estudio de 120 biopsias de adenomas pituitarios con inmunohistoquímica y microscopía electrónica. Correlación clínico-patológica.

Study of biopsies from 120 pituitary adenomas from the Hospital de Especialidades, Centro Médico Nacional, and the Hospital 20 de Noviembre, ISSSTE, were studied over a period of 55 months. 70 cases were female and 50 male. Ages varied between 18 and 67 years of age (with an average of 31 years). Histologically 41 tumors were chromophobes, 34 acidophilic, 37 mixed and 8 basophilic. 101 patients were operated by trans-sphenoidal (84.5%) and 19 were operated (15.5%) by trans-cranial approaches. 99 tumors were macroadenomas (81.1%) and 21 were microadenomas (18.9%). More than one hormone was found in the cytoplasm of 69 adenomas, although only 20 fulfilled the criteria of being plurihormonal. Those adenomas classified as "non-functional", mostly produced glycoprotein hormones corresponding to oncocytomas and null cell adenomas, from an ultrastructural point of view. 85 patients developed different degrees of visual impairment, with 30 tumoral relapses, of which 10 received radiotherapy. 40 adenomas produced prolactin, although only 29 patients developed clinical signs of hyperprolactinemia; 38 tumors contained growth hormone, of which only 25 had acromegaly; 8 tumors contained ACTH in the cytoplasm, although only 7 developed Cushing's Syndrome and 57 patients (47.5%) were classified as nonfunctional and did not show any endocrinological data. All the cases are studied with a light microscope, electron microscope, and they were all submitted to a complete set of adenohypophyseal hormone with immunoperoxidase technique.