Atypical sites of lymphoma in the central nervous system

Locais atípicos de linfoma no sistema nervoso central

LETTERS

Atypical sites of lymphoma in the central nervous system

Locais atípicos de linfoma no sistema nervoso central

Ricardo Schwingel^I; Fabiano Reis^II; Veronica Zanardi^II; Luciano Queiroz^III; Marcondes França Jr^IV

^IMedical Student, UNICAMP, Departments of Radiology (RS, FR, VZ), Pathology (LQ) and Neurology (MFJr), School of Medical Sciences, State University of Campinas (UNICAMP), Campinas SP, Brazil

^IIMD, PhD, Professor, Department of Radiology,Departments of Radiology (RS, FR, VZ), Pathology (LQ) and Neurology (MFJr), School of Medical Sciences, State University of Campinas (UNICAMP), Campinas SP, Brazil

^IIIMD, PhD, Professor, Department of Pathology, Departments of Radiology (RS, FR, VZ), Pathology (LQ) and Neurology (MFJr), School of Medical Sciences, State University of Campinas (UNICAMP), Campinas SP, Brazil

^IVMD, PhD, Professor, Department of Neurology, Departments of Radiology (RS, FR, VZ), Pathology (LQ) and Neurology (MFJr), School of Medical Sciences, State University of Campinas (UNICAMP), Campinas SP, Brazil

^{Correspondence}

CASE

A 51 -year -old immunocompetent man presented left-side third nerve palsy. He had previously been diag-nosed eight years earlier with an axillary large-cell non-Hodgkin lymphoma (NHL), which had been treated with chemotherapy and radiotherapy. MRI showed pineal and hypothalamic lesions (Fig A and B) and computed to-mography of the abdomen showed a spleen lesion. After splenectomy, the diagnosis of NHL was made. Laboratory findings showed enhanced serum lactate dehydroge-nase (LDH) levels (594 U/l; reference value: 479 U/l) and enhanced IgG levels in the cerebrospinal fluid (15.4 mg/ dl; reference value: 3.4 mg/dl). Increased protein con-tent and cell counts in the cerebrospinal fluid were also observed. The patient was treated with chemotherapy. Eleven months later, the pineal and hypothalamic lesions had disappeared, but a lesion had appeared in the right inferior horn of the right lateral ventricle (Fig C and D).

Shortly afterwards, the patient's clinical condition dete-riorated and he died.

DISCUSSION

In a case of pineal gland lymphoma reported in the literature, the lesion appeared to be similar to primary tumors of pineal origin (pineocytoma and pineoblas-toma), or even to germinoma (which may also show an intermediate signal on T1 and hypointense signal on T2, due to a high nucleus/cytoplasm ratio)¹. However, ger-minoma is a tumor of adolescence and young adulthood. A second case showed a lesion with cystic and nodular components simultaneously². Imaging examinations may also show heterogeneous enhancement with thick nod-ular enhancement of the leptomeninges³.

In a case of lymphoma in the hypothalamic region, the lesion appeared to be hypointense on T1- weighted images and showed intense and homogeneous enhance-ment after contrast injection⁴. Two other cases reported isointense masses on T1-weighted images, with het-erogeneous contrast enhancements and erosion of sur-rounding bone structures⁵. Infundibulum metastases are usually isointense on T1-weighted images and are enhanced by contrast. On T2, lymphoma in the hypo-thalamic and pineal region may show hypointensity due to a high nucleus/cytoplasm ratio, as we observed in our patient.

Although the histological diagnosis can often be sus-pected from the radiological characteristics of the lesion, few pineal and hypothalamic tumors have pathogno-monic imaging patterns. Histological diagnosis is nec-essary for primary tumors, because both regions can be affected independently by a variety of benign and malig-nant tumors. Our patient was not subjected to biopsy of the intracranial tumor, but the diagnosis of lymphoma was plausible, because of his clinical history and high LDH level, and because of the disappearance of the le-sion after chemotherapy for the concurrent lymphoma, as confirmed by the spleen biopsy. However, after 11 months, a lesion was detected in the choroid plexus, an-other rare site for occurrences of lymphoma.

In conclusion, we have presented a case with atyp-ical sites for CNS lymphoma occurrence. This diagnosis should be considered if the patient has previously had systemic lymphoma, with involvement of more than one extranodal site and a high LDH level (which are the main independent risk factors for recurrence of lymphoma in the CNS), and later develops important symptoms for a diagnosis of tumor recurrence in the CNS. Although such radiological findings are unusual, they may aid the diagnostic differentiation, particularly if the lesion shows a hypointense signal on T2.

Received 6 January 2011

Received in final form 10 March 2011

Accepted 18 March 2011

Support: FAPESP process no. 2010/01939-0.

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Publication Dates

• Publication in this collection
  19 July 2012
• Date of issue
  June 2011