Images in Pediatric Neurosurgery Pediatr Neurosurg 2013;49:60–61 DOI: 10.1159/000355564
Received: June 28, 2013 Accepted after revision: September 6, 2013 Published online: October 29, 2013
Calcified Rock-Like Medulloblastoma Sameer Futane a Pravin Salunke a Ankur Kapoor a Kim Veiphei b Departments of a Neurosurgery and b Histopathology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
Calcifications are not very common in medulloblastomas [1, 2]. In the present case we describe a very unique finding of a largely calcified, rock-like medulloblastoma. A 4-year-old boy presented with altered sensorium, with a history of intermittent headache and ataxia for 2 months. CT showed a 5 × 4 cm mass with near-complete calcification in the posterior fossa along with hydrocephalus. The hyperdense area on CT measured 180 Hounsfield units. He immediately underwent ventriculoperitoneal shunting, after which he regained sensorium. T1-weighted MRI showed a hypointense and T2-weighted MRI a slightly hyperintense posterior fossa mass. Contrast MRI showed a mixed density, the contrast enhancing the mass occupying the fourth ventricle with a left peripheral cystic component (fig. 1a–e). Gradient echo sequences confirmed the calcification of nearly the entire lesion. Another smaller lesion was seen in the suprasellar region. The MRI features of the suprasellar mass were similar to those of the posterior fossa mass. CT did not show any hyperdense areas other than that seen in the posterior fossa mass. Preoperative spinal MRI was not performed. Cerebrospinal fluid cytology did not show malignant cells. The patient underwent a midline suboccipital craniotomy. The telovelotonsillar fissure was split. The tumor appeared gritty, calcified and moderately vascular. Calcified areas were chunky and hard, though brittle, and they required crushing to aid their removal. An engulfed branch of the posterior inferior cerebellar artery required careful dissection. There was evidence of hemorrhage with tonsillar herniation. © 2013 S. Karger AG, Basel 1016–2291/13/0491–0060$38.00/0 E-Mail [email protected] www.karger.com/pne
Gross total excision of the tumor was achieved. The floor of the fourth ventricle was normal and a free flow of cerebrospinal fluid from the aqueduct could be seen at the end of surgery. Histopathology sections showed tumor cells to comprise hyperchromatic oval- to spindle-shaped nuclei arranged haphazardly in a large area with a prominent nodular appearance. The tumor had nodular zones that were reticulin poor and surrounded by reticulin-rich zones; areas of necrosis, mitosis (2–3/10 high-power fields) and dystrophic calcification were seen. Overall features were suggestive of desmoplastic medulloblastoma (fig. 1f–h). The immediate postoperative course was uneventful. The headache improved significantly. However, the improvement in ataxia was partial. Six weeks later, MRI of the craniospinal axis revealed only the suprasellar mass, as in preoperative images. The patient subsequently underwent radiotherapy. Unfortunately, the child died 3 months after surgery. The cause of death remains speculative, as he died before postradiation MRI could be done and the parents refused an autopsy. Calcification is present in 22% of medulloblastoma cases [2]. Most of these are stippled, punctate calcifications, rarely large and chunky [2]. In our case, nearly the whole lesion was seen to be calcified, which makes it unusual. Desmoplastic medulloblastomas tend to be more calcified than other variants [2]. Ependymomas and oligodendrogliomas have been reported with such large calcium deposits [1]. Apart from diagnostic dilemma, such calcified medulloblastomas pose a surgical challenge. The Dr. Pravin Salunke, Assistant Prof. PGIMER, Sector 12 Chandigarh 160012 (India) E-Mail drpravin_salunke @ yahoo.co.uk
Color version available online
a
e
b
f
c
d
g
h
Fig. 1. a Plain CT scan showing calcified rock-like posterior fossa mass. b, c Axial and sagittal contrast MRI scans showing a heterogeneously enhancing mass in the posterior fossa. d T2-weighted MRI scan showing a flow void in the central part of the tumor. e Postoperative scan showing complete excision of the lesion. No calcified part is left. The suprasellar mass can be appreciated in all
the images. f Medium-power photomicrograph showing tumor cells arranged in pale nodular areas. HE. ×250. g Medium-power photomicrograph showing reticulin-poor areas corresponding to the pale nodular areas, intervened by darker, reticulin-rich areas. Reticulin. ×250. h Low-power photomicrograph of the tumor to show areas of hyalinization and calcification. HE. ×150.
central flow void surrounded by dense calcium, as seen in figure 1b, suggests a vessel loop. Such a vessel may be adherent to the calcified tumor, and casual pulling of this tissue is likely to tear the vessel or yank it from its origin at the posterior-inferior cerebellar artery. These torrential bleeds can be avoided by carefully studying the preoperative images and by intraoperative precaution. Additionally, trying to remove the large chunks in one go results in traction on the cerebellar peduncles, vessels and indirectly on the brain stem. A cavitron ultrasonic suction aspirator, if available, is likely to be helpful in such cases.
The process of dystrophic calcification begins with crystal formation by calcium and phosphates aided by phosphatases [3]. The propagation of such crystal formation is facilitated by the concentration of calcium, phosphates, inhibitors and connective tissue matrix proteins [3]. The desmoplastic variants probably provide such a milieu of connective tissue matrix proteins in abundance, so as to form calcified varieties. However, the reason for the origin of such rock-like medulloblastomas is unknown. Surgical warning appears to be warranted by this rather unique incidental radiological abnormality.
References 1 Gunjan B, Epari S, Jalali R: Medulloblastoma presenting as a non-lateralized calcified stone like mass in an adult. Neurol India 2011; 59: 319–320.
Calcified Rock-Like Medulloblastoma
2 Koeller KK, Rushing EJ: From the archives of the AFIP: medulloblastoma – a comprehensive review with radiologic-pathologic correlation. Radiographics 2003;23:1613–1637.
3 Kumar V, Abbas AK, Fausto N, Stanley L: Cellular adaptations, cell injury, and cell death; in Kumar V, Abbas AK, Fausto N (eds): Robbins and Cotran: Pathologic Basis of Disease, ed 7. Philadelphia, Elsevier Saunders, 2005, pp 41–42.
Pediatr Neurosurg 2013;49:60–61 DOI: 10.1159/000355564
61
Copyright: S. Karger AG, Basel 2013. Reproduced with the permission of S. Karger AG, Basel. Further reproduction or distribution (electronic or otherwise) is prohibited without permission from the copyright holder.
Received: June 28, 2013 Accepted after revision: September 6, 2013 Published online: October 29, 2013
Calcified Rock-Like Medulloblastoma Sameer Futane a Pravin Salunke a Ankur Kapoor a Kim Veiphei b Departments of a Neurosurgery and b Histopathology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
Calcifications are not very common in medulloblastomas [1, 2]. In the present case we describe a very unique finding of a largely calcified, rock-like medulloblastoma. A 4-year-old boy presented with altered sensorium, with a history of intermittent headache and ataxia for 2 months. CT showed a 5 × 4 cm mass with near-complete calcification in the posterior fossa along with hydrocephalus. The hyperdense area on CT measured 180 Hounsfield units. He immediately underwent ventriculoperitoneal shunting, after which he regained sensorium. T1-weighted MRI showed a hypointense and T2-weighted MRI a slightly hyperintense posterior fossa mass. Contrast MRI showed a mixed density, the contrast enhancing the mass occupying the fourth ventricle with a left peripheral cystic component (fig. 1a–e). Gradient echo sequences confirmed the calcification of nearly the entire lesion. Another smaller lesion was seen in the suprasellar region. The MRI features of the suprasellar mass were similar to those of the posterior fossa mass. CT did not show any hyperdense areas other than that seen in the posterior fossa mass. Preoperative spinal MRI was not performed. Cerebrospinal fluid cytology did not show malignant cells. The patient underwent a midline suboccipital craniotomy. The telovelotonsillar fissure was split. The tumor appeared gritty, calcified and moderately vascular. Calcified areas were chunky and hard, though brittle, and they required crushing to aid their removal. An engulfed branch of the posterior inferior cerebellar artery required careful dissection. There was evidence of hemorrhage with tonsillar herniation. © 2013 S. Karger AG, Basel 1016–2291/13/0491–0060$38.00/0 E-Mail [email protected] www.karger.com/pne
Gross total excision of the tumor was achieved. The floor of the fourth ventricle was normal and a free flow of cerebrospinal fluid from the aqueduct could be seen at the end of surgery. Histopathology sections showed tumor cells to comprise hyperchromatic oval- to spindle-shaped nuclei arranged haphazardly in a large area with a prominent nodular appearance. The tumor had nodular zones that were reticulin poor and surrounded by reticulin-rich zones; areas of necrosis, mitosis (2–3/10 high-power fields) and dystrophic calcification were seen. Overall features were suggestive of desmoplastic medulloblastoma (fig. 1f–h). The immediate postoperative course was uneventful. The headache improved significantly. However, the improvement in ataxia was partial. Six weeks later, MRI of the craniospinal axis revealed only the suprasellar mass, as in preoperative images. The patient subsequently underwent radiotherapy. Unfortunately, the child died 3 months after surgery. The cause of death remains speculative, as he died before postradiation MRI could be done and the parents refused an autopsy. Calcification is present in 22% of medulloblastoma cases [2]. Most of these are stippled, punctate calcifications, rarely large and chunky [2]. In our case, nearly the whole lesion was seen to be calcified, which makes it unusual. Desmoplastic medulloblastomas tend to be more calcified than other variants [2]. Ependymomas and oligodendrogliomas have been reported with such large calcium deposits [1]. Apart from diagnostic dilemma, such calcified medulloblastomas pose a surgical challenge. The Dr. Pravin Salunke, Assistant Prof. PGIMER, Sector 12 Chandigarh 160012 (India) E-Mail drpravin_salunke @ yahoo.co.uk
Color version available online
a
e
b
f
c
d
g
h
Fig. 1. a Plain CT scan showing calcified rock-like posterior fossa mass. b, c Axial and sagittal contrast MRI scans showing a heterogeneously enhancing mass in the posterior fossa. d T2-weighted MRI scan showing a flow void in the central part of the tumor. e Postoperative scan showing complete excision of the lesion. No calcified part is left. The suprasellar mass can be appreciated in all
the images. f Medium-power photomicrograph showing tumor cells arranged in pale nodular areas. HE. ×250. g Medium-power photomicrograph showing reticulin-poor areas corresponding to the pale nodular areas, intervened by darker, reticulin-rich areas. Reticulin. ×250. h Low-power photomicrograph of the tumor to show areas of hyalinization and calcification. HE. ×150.
central flow void surrounded by dense calcium, as seen in figure 1b, suggests a vessel loop. Such a vessel may be adherent to the calcified tumor, and casual pulling of this tissue is likely to tear the vessel or yank it from its origin at the posterior-inferior cerebellar artery. These torrential bleeds can be avoided by carefully studying the preoperative images and by intraoperative precaution. Additionally, trying to remove the large chunks in one go results in traction on the cerebellar peduncles, vessels and indirectly on the brain stem. A cavitron ultrasonic suction aspirator, if available, is likely to be helpful in such cases.
The process of dystrophic calcification begins with crystal formation by calcium and phosphates aided by phosphatases [3]. The propagation of such crystal formation is facilitated by the concentration of calcium, phosphates, inhibitors and connective tissue matrix proteins [3]. The desmoplastic variants probably provide such a milieu of connective tissue matrix proteins in abundance, so as to form calcified varieties. However, the reason for the origin of such rock-like medulloblastomas is unknown. Surgical warning appears to be warranted by this rather unique incidental radiological abnormality.
References 1 Gunjan B, Epari S, Jalali R: Medulloblastoma presenting as a non-lateralized calcified stone like mass in an adult. Neurol India 2011; 59: 319–320.
Calcified Rock-Like Medulloblastoma
2 Koeller KK, Rushing EJ: From the archives of the AFIP: medulloblastoma – a comprehensive review with radiologic-pathologic correlation. Radiographics 2003;23:1613–1637.
3 Kumar V, Abbas AK, Fausto N, Stanley L: Cellular adaptations, cell injury, and cell death; in Kumar V, Abbas AK, Fausto N (eds): Robbins and Cotran: Pathologic Basis of Disease, ed 7. Philadelphia, Elsevier Saunders, 2005, pp 41–42.
Pediatr Neurosurg 2013;49:60–61 DOI: 10.1159/000355564
61
Copyright: S. Karger AG, Basel 2013. Reproduced with the permission of S. Karger AG, Basel. Further reproduction or distribution (electronic or otherwise) is prohibited without permission from the copyright holder.
