Page 27 - Read Online

Figure 1: Axial head computed tomography image revealing a predominantly
hypodense mass lesion in the cerebellum, centered at the vermis. The
lesion compresses the fourth ventricle (arrow pointing to the mass)

was avid internal enhancement of the lesion on post- Figure 2: Axial magnetic resonance imaging images of fluid-attenuated
contrast images. Additionally there was a thin tract of inversion recovery (a) and T1 postcontrast (b) at initial presentation and then
postoperatively (c and d) revealing complete radiographic resection of the lesion
contrast enhancement extending from the lesion along
the right lateral margin of the brainstem. There was mild
edema of the surrounding cerebellum. occurs predominantly by inhalation of the microconidia
of the dimorphic fungus B. dermatitidis. The fungus
Differential diagnosis of the posterior fossa mass in a is prevalent in the areas along the Mississipi and Ohio
41 years old male included neoplastic (high- or low- river basins as well as Midwestern regions bordering
grade gliomas, medulloblastoma, hemangioblastoma, the Great Lakes. About 91% of infections are pulmonary
lymphoma and infectious etiologies. Pilocytic with subsequent dissemination to the skin, bone or
astrocytomas (WHO grade I) and medulloblastomas genitourinary system. CNS involvement occurs only
[1]
(WHO grade IV) occur more frequently in the pediatric rarely 5-10% of cases. Isolated CNS blastomycosis is
rare. Infection occurs in both immunocompetent and
population. CNS lymphomas occur more frequently in immunosuppressed hosts. For example, in a case series of
the elderly or HIV+ population. Hemangioblastomas often 22 patients with CNS blastomycosis, only 12 patients were
occur in association with Von Hippel-Lindau syndrome. immunocompromised (i.e. HIV, chronic steroid use, anti-
Other than the suspicion of alcohol abuse, patient was tumor necrosis factor therapy for more than 6 months).
[2]
otherwise not immunocompromised. He was HIV Clinical and experimental evidence (predominantly
negative, lacked peripheral leukocytosis, fevers, and had animal studies) suggests that chronic alcohol consumption
an unremarkable CT of the chest. Given the location, the significantly alters many lines of immune system and
size, and the mass effect of the lesion, no lumbar puncture predisposes alcoholics to an increased risk of infection,
could be pursued due to the risk of herniation. The increased morbidity, and mortality.
[3]
patient underwent a suboccipital craniotomy achieving
a complete resection. Pathology showed granulomas CNS blastomycotic infection can present as either
with fungal organisms. Periodic acid-Schieff and Giemsa acute or indolent meningoencephalitis. At times, the
(GMS) stains revealed rounded yeast forms consistent only symptoms are intractable headaches. In a recent
with Blastomycosis dermatitidis [Figure 3]. Post-operative study that evaluated outcomes of 16 patients with CNS
cerebrospinal fluid (CSF) revealed > 1,000 White blood blastomycosis, the most frequent symptoms at presentation
cells with neutrophilic predominance, normal glucose at were headaches or a focal neurologic deficit in 63 and
[4]
64 and high protein at 300. 56% of patients respectively. Other manifestations
include leptomeningeal involvement, single or multiple
DISCUSSION abscesses intracranially or in the spinal cord, as well as
in the epidural space causing cord compression. On the
Blastomycosis is a pyogranulomatous infection that MRI these may present as a single or multiple lesions

18 Neuroimmunol Neuroinfammation | Volume 3 | Issue 1 | January 20, 2016