Brain Pathology Case of the Month - December 2006

Contributed by Mahlon D. Johnson, M.D., Ph.D., Charles B. Stevenson, M.D.1, Reid C. Thompson, M.D.1, James Atkinson, M.D., Ph.D.2, and Phillip Boyer, M.D., Ph.D.3
Department of Pathology, University of Tennessee Medical Center, Knoxville, Tennessee; Departments of 1Neurological Surgery and 2Pathology, Vanderbilt University Medical Center, Nashville, Tennessee; and 3Department of Pathology, University of Texas Southwestern Medical Center, Dallas, Texas


A 31-year-old, previously healthy woman experienced a new-onset generalized seizure with subsequent right-sided weakness in the 37th week of her pregnancy. History revealed no significant nausea or vomiting (other than that associated with the first trimester of pregnancy) and no prior history of seizures. The patient did, however, report a history of slowly-increasing weakness in her right leg over the past several months. Routine prenatal care had been uneventful and negative for gestational diabetes or hypertension.

Neurologic examination on admission revealed a young woman who was somnolent but easily arousable. She demonstrated a moderate right-sided hemiparesis with 3 to 4-/5 strength in the right lower extremity and 4/5 strength in the right upper extremity. A mild right-sided facial droop was also present. Babinski sign was present bilaterally, and fundic exam revealed papilledema bilaterally.

Initial evaluation with cranial CT scans demonstrated a large left parasagittal mass with midline shift. MRI of the brain revealed a robustly enhancing 7.8 x 4.6 cm left frontal lobe mass lesion adjacent to the falx cerebri (Fig. 1). It effaced the left lateral ventricle and was associated with significant mass effect resulting in 1.5 cm of midline shift. T2 sequences revealed marked vasogenic edema extending throughout most of the left cerebral hemisphere.

The patient was placed on intravenous dexamethasone and loaded with phenytoin for seizure prophylaxis. On the day following admission she was brought to the operating room by the obstetrics service for cesarean section under general anesthesia. This was performed without complication to mother or child. Approximately 24 hours postoperatively the patient developed recurrent generalized seizure activity and became progressively lethargic and ultimately comatose with non-reactive pupils. This decline in her neurologic exam was accompanied by persistent hypertension and bradycardia suggestive of increased ICP. Repeat imaging revealed only continued mass effect and midline shift from the tumor without evidence of hemorrhage. She was treated aggressively with mannitol and high-dose glucocorticoids to which she had a dramatic clinical response--she was once again awake, conversant, and able to follow commands.

Six days post-cesarian section the patient remained clinically stable on mannitol and steroids and was taken to the operating room for craniotomy. Intraoperatively, the tumor had the gross appearance and consistency of a meningioma. It was found to arise from the falx cerebri, from which most of its blood supply originated. A gross-total resection was achieved. A postoperative MRI scan revealed an image-complete resection (Fig. 1). The patient's postoperative course was complicated by hemiparesis and transient severe depression. By six weeks postoperatively the patient was doing extremely well and had made a complete neurologic recovery.


Hematoxylin and eosin-stained sections revealed a myxoid, spindle cell tumor with hypo- and hypercellular areas. There was no evidence of mitoses, necrosis, inflammation, or granulomas (Fig. 2 and 3). One focus with a vague meningothelial pattern and a nuclear pseudoinclusion was found (Fig. 4). The tumor stained diffusely with Alcian blue, pH 2.5, (Fig. 5) and PAS. No keloid-like collagen or slit-like vascular pattern was found, and CD34 immunohistochemistry was negative. A reticulin stain demonstrated scattered reticulin fibers within the myxoid extracellular material. Tumor cells exhibited no significant epithelial membrane antigen (EMA) immunostaining at a dilution of 1:400 but did demonstrate immunoreactivity at dilutions of 1:100 and 1:40. There was no AE1/AE3 (repeated), CAM 5.2, smooth muscle actin, muscle-specific actin, myogenin, CD34, glial fibrillary acidic protein, or S-100 protein immunoreactivity. CD68 immunohistochemistry demonstrated only rare monocytes. Electron microscopic analysis revealed external lamina around some cells and showed evidence of primitive cell junctions (Fig. 6).


International Society of Neuropathology