Absence of enhancement in a lesion does not preclude primary central nervous system T-cell lymphoma: A case report

Table 1 The summary of patient's clinical symptoms, exam results, considered diagnosis, and treatment

Time	Initial	5 d after	1 month after
Neurologic symptom	Mild cognitive impairments	No significant change in MRC grade 3 left lower leg weakness	Changed mental status to comatose
	MRC grade 3 left lower leg weakness
MRI	Asymmetric hyperintensities at the bilateral periventricular white matters, basal ganglia, thalamus, cerebral and cerebellar peduncles	No significant change in extent of T2 hyperintense lesion	Reduced extent of T2 hyperintense lesion in right basal ganglia, but increased extent in left hemisphere compressing left lateral ventricle
			Newly appeared SAH
Laboratory exams	Slight elevation of WBC in CSF	Nonspecific	Nonspecific
Considered diagnoses	Neuro-Behçet’s disease	Neuro-Behçet’s disease	Glioblastoma
			Lymphoma
			Metastasis
Treatment	Prednisolone at 1 mg/d for 5 d	None	Supportive care for bacteremia and sepsis

MRC: Medical Research Council; WBC: White blood cell; CSF: Cerebrospinal fluid; SAH: Subarachnoid hemorrhage; MRI: Magnetic resonance imaging.

Table 2 The pathologic report

Immunohistochemical	P53: Positive
	CD68: Positive in the microglia
	Glial Fibrillary Acidic Protein: Positive in the reactive astrocytes
	Myeloperoxidase: Negative
	K27M: Negative
	Vimentin: Focal positive in the lymphocytes and reactive astrocytes
	CD56: Nonspecifically positive
	Phospho-Histone H3: 23/10 HPFs
	LFB: Positive in the myelin sheath (no loss of myelin sheath)
	Isocitrate Dehydrogenase 1: Negative (no mutation)
	EZHIP: Negative
	Olig2: Focal positive
	TMHH3 (Lys27): Positive (no mutation)
	CD3: Some CD3-positive T-cells infiltration
	CD20: A few positive cells in a perivascular area
	IBA-1: Positive in the microglia
	Ki-67: Positive in 40.0%
	CD8: A few positive cells
Electronic microscopy	Ultrathin sections show sheets of round to oval-shaped neoplastic lymphoid cells. The nuclei of tumor cells are round to oval with heterochromatin and prominent nucleoli. The cytoplasm is scanty and contains eccentrically located a few mitochondria and electron-dense granules
Diagnosis	Brain, putamen, left, stereotactic biopsy: Scattered proliferative T-cell infiltration, consistent with T-cell lymphoma

CD: Cluster of differentiation; LFB: Luxol fast blue; EZHIP: Enhancer of Zest homologs inhibitory protein; Olig2: Oligodendrocyte transcription factor 2; TMHH3 (lys27): Trimethylation at lysine 27 of histone H3; IBA-1: Ionized calcium-binding adaptor molecule 1; Ki-67: Antigen Kiel-67.