Images in Neuroscience: Answer Painless skull mass in a 70-year-old man Naif M. Alotaibi a,b,1 , Alireza Mansouri a,⇑ , Michael D. Staudt a,1 , Felipe G. Carvalho a , Fred Gentili a a Division of Neurosurgery, Department of Surgery, University of Toronto, 399 Bathurst Street, WW 4-427 Toronto, ON M5T 2S8, Canada b Department of Neurosurgery, National Neuroscience Institute (NNI), King Fahad Medical City, Saudi Arabia 1. Answer C. Lymphoma. 2. Discussion The patient underwent subtotal surgical resection to debulk the tumor and to obtain a tissue diagnosis. Infiltration was seen intra- operatively throughout the scalp and the calvarial bones (Fig. 1). Specimens revealed dense monotonous infiltrates of lymphoid cells expressing CD45, CD20, CD5, CD43, CD23, and CD21. There was no expression of CD10, Bcl-6, cyclin D1, CD138, or TdT. Epstein-Barr encoding region in situ hybridization was negative for Epstein Barr virus. Approximately 90% of cells were P53 posi- tive, and 15–20% of cells were positive for the proliferation marker MIB-1. Bone marrow biopsy and aspirate revealed findings of atypical small lymphocytic lymphoma. The patient was referred to medical oncology as no further surgical intervention or radiation therapy was deemed necessary. Cranial vault involvement in advanced stages of lymphoma is rare [1]. The spaces within the diploe and the emissary veins are the main routes for lymphoma cells to infiltrate the soft tissues on either side of the bone [2]. A painless skull mass is the most common presentation [3]. Headache usually results from bone destruction or tumor infiltration of meninges. The radiographic features of lymphoma can appear similar to other cranial lesions, including subdural hematoma, metastatic infiltration, osteomyeli- tis, plasma cell tumors, and meningioma. CT scan and MRI of cranial vault lymphomas are not definitively diagnostic. However, involvement of the meninges or cortex on neurological imaging has been reported to predict invasion in a number of patients [1]. The optimal management of these lesions is unknown, and previ- ously reported treatment options have included a combined modality treatment of surgical resection, radiation and chemother- apy. Comprehensive staging is an important prerequisite to treat- ment. Surgical resection is rarely curative, and is mainly used for diagnosis. Given the paucity of cases reported in the literature and the indolent course of cranial vault lymphoma, the prognosis is unknown. Conflicts of interest/disclosures The authors declare that they have no financial or other con- flicts of interest in relation to this research and its publication. References [1] da Rocha AJ, da Rocha TM, da Silva CJ, et al. Cranial vault lymphoma: a systematic review of five patients. J Neurooncol 2010;100:9–15. [2] Aquilina K, O’Brien DF, Phillips JP. Diffuse primary non-Hodgkin’s lymphoma of the cranial vault. Br J Neurosurg 2004;18:518–23. [3] El Asri AC, Akhaddar A, Baallal H, et al. Primary lymphoma of the cranial vault: case report and a systematic review of the literature. Acta Neurochir (Wien) 2012;154:257–65 [discussion 265]. Fig. 1. Operative photograph. Infiltration was seen intra-operatively throughout the layers of the scalp and the calvarial bones overlying the parietal and posterior frontal lobes. (B) Examination of the gross specimen revealed a gray, flesh-like and rubbery lesion. (This figure is available in colour at www.sciencedirect.com) 0967-5868/$ - see front matter Ó 2014 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jocn.2013.11.001 doi of question: http://dx.doi.org/10.1016/j.jocn.2013.08.024 ⇑ Corresponding author. Tel.: +1 416 603 5800x5503. E-mail address: alireza.mansouri@utoronto.ca (A. Mansouri). 1 These authors have contributed equally to the manuscript. Journal of Clinical Neuroscience 21 (2014) 708 Contents lists available at ScienceDirect Journal of Clinical Neuroscience journal homepage: www.elsevier.com/locate/jocn