Brain Pathology Case of the Month - October 2003

Contributed by Rafael Medina-Flores, MD1, Anand Germanwala, MD2, J. Thomas Molina, MD, PhD1, Carolyn C Meltzer, MD3, and Clayton A Wiley, MD, PhD1
  Departments of 1 Pathology (Neuropathology), 2Neurological Surgery and 3Radiology (Neuroradiology), University of Pittsburgh School of Medicine.
Published on line in October 2003


A 59-year-old woman experienced sudden onset of horizontal binocular diplopia and right-sided facial paresthesias. The patient was in her usual state of good health until one week before, when she began complaining of severe occipital headaches. She was able to continue her routine activities although her diplopia did not subside. At work, her colleagues thought her right face drooped. The patient had a past medical history that was significant for hypertension, non-insulin dependent diabetes mellitus, coronary artery disease, hypothyroidism and dental implants placed four weeks before the onset of symptoms.

On physical examination the patient was afebrile, awake and oriented. Cranial nerve examination revealed equal and reactive pupils, the visual fields were full to confrontation bilaterally. Extraocular movements were full both horizontally and vertically. However, she experienced horizontal diplopia with distant vision. Sensation was intact to light touch, pinprick and temperature over the face; however, the corneal reflex was absent on the right side. The face was asymmetric with marked settling of the right nasolabial fold. The tongue was midline, and the uvula and palate elevated symmetrically. Motor examination revealed normal and equal fine motor movements bilaterally. Strength was normal throughout. Sensory examination revealed mild loss of pinprick sensation in her lower extremities, and was otherwise intact to light touch and temperature. There was normal finger-to-nose coordination bilaterally and no evidence of ataxia. Reflexes were normal and symmetrical throughout. The remainder of the physical exam was unremarkable.

MRI of the brain revealed a 1.3 x 1.3 x 1.5 cm ring-enhancing lesion with central hypointensity, predominantly located in the left cerebral peduncle (Figures 1, 2), extending inferiorly to the pons at the level of the brachium pontis. There was a significantly increased T2 signal (Figure 3), which extended superiorly to the level of the posterior limb of the left internal capsule, medially throughout the entire pons, and inferiorly to the left pontomedullary junction.

The patient underwent a CT guided stereotactic biopsy. After performing a left frontal twist drill craniostomy, a dural puncture needle was inserted and advanced into the brainstem. Aspiration was then performed with a small gauge needle, yielding approximately 2.0 ml of liquid purulent material.


A hematoxylin and eosin stained smear of the purulent material shows intense acute inflammation (Figure 4). Gram stain disclosed numerous intra and extracellular, gram-positive bacilli. (Figure 5). At forty-eight hours, cultures of the aspirated material on blood agar, grew small, gray-blue, translucent, beta-hemolytic colonies. A catalase reaction was positive.


International Society of Neuropathology