Neurology India Medknow Publications on behalf of the Neurological Society of India ISSN: 0028-3886 EISSN: 1998-4022 Vol. 52, Num. 3, 2004, pp. 387-390

Neurology India, Vol. 52, No. 3, July-September, 2004, pp. 387-390

Short Reports

Calvarial malignant fibrous histiocytoma

Chhabra R, Gupta SK, Manjunath Prasad KS, Gupta D, Vasishta RK, Sharma RK, Khosla VK

Departments of Neurosurgery, PGIMER, Chandigarh
Correspondence Address:Department of Neurosurgery, PGIMER, Chandigarh - 160012 sktulika@yahoo.com

Code Number: ni04127

ABSTRACT

KEY WORDS: Malignant fibrous histiocytoma, scalp, skull

INTRODUCTION

Malignant fibrous histiocytoma (MFH) is a common soft tissue tumor in adults occurring in the 5^th to 7^th decades of life and accounts for 10.5% to 21.6% of all soft tissue malignant neoplasms.[1] The primary incidence involving the central nervous system (CNS) was described by Gonzalez-Vitale et al[2] in 1976. Since then there have been only few sporadic case reports of MFH involving the CNS.[2],[3],[4],[5],[6],[7],[8],[9],[10],[11],[12],[13],[14]

We report two young patients with malignant fibrous histiocytoma presenting as rapidly growing skull tumors.

Case No. 1

A 25-year-old female presented with a swelling over the left parieto-occipital area for the past five months. The swelling showed ulcerative changes two months prior to admission in hospital. There was intermittent bleeding and purulent discharge from the swelling. There was local pain and mild fever with occasional vomiting. There was no history of trauma.

On examination the patient was anemic and had no neurological deficit. There was a 15cm x 20cm globular mass in the left parieto-occipital region with area of ulceration and necrosis of the overlying scalp. The swelling was firm, non-tender, involving the scalp and the underlying bone. It had well-defined margins and was fixed to the bone. Skull roentgenogram revealed a soft tissue mass in the occipital area with bony destruction in the left parieto-occipital region [Figure - 1]. CT scan showed a mixed density mass with bony destruction. The heterogeneously enhancing mass showed involvement of the left occipital cortex [Figure- 2]. Fine needle aspiration cytology (FNAC) was suggestive of a giant cell tumor.

At surgery, the fungating scalp tumor was excised with a rim of healthy bone all around including the intracranial extension and along with the involved dura. The tumor was very vascular, and was seen infiltrating the left occipital lobe. Growth of the tumor into the superior sagittal sinus, left transverse sinus and torcula was seen at surgery. The tumor infiltrating into the occipital lobe was excised but the extension into the venous sinuses was not removed. The defect created by the dural excision was patched with fascia lata. Skin cover for a 10 x 15-cm scalp defect was provided by a rotation flap, based on the superficial temporal artery. The secondary de fect in the scalp was covered by a split thickness skin graft. Cranioplasty was not performed due to the presence of areas of ulceration and infection. Microscopic examination showed the tumor to be poorly encapsulated. There was a prominent plump spindle cell stroma with focal storiform pattern. Marked nuclear pleomorphism and atypia with a few multinucleated giant cells were seen. Areas of necrosis were present. There were no lipoblasts or cells with striations. Inflammatory cells such as lymphocytes and neutrophils were present focally. The combination of pleomorphism and spindled stroma with focal storiform pattern suggested a diagnosis of malignant fibrous histiocytoma. Postoperative radiotherapy was advised but the patient refused further treatment and did not follow up.

Case No. 2

A 22-year-old male was admitted with history of a rapidly growing swelling in left temporal region for the past two months. On examination the swelling was situated in the left temporal region just above and anterior to the pinna. It was a 7x5-cm globular, firm and mildly tender mass, fixed to the underlying bone, with well-defined margins. A contrast CT scan demonstrated an enhancing mass in the left temporal region with underlying bone destruction [Figure - 3]. At surgery, the temporal bone was eroded and destroyed but the cortical surface of the brain was intact. The mass was excised along with the middle fossa dura, which was involved. Repair was done using a fascia lata graft. Postoperatively, the patient had a CSF leak, which was managed by a lumbar drain. Postoperative CT showed gross total excision [Figure - 4]. He was referred for radiotherapy. He had a local recurrence 1 month later and was advised chemotherapy but refused treatment. Histological examination showed a pleomorphic tumor composed of short fascicles of spindle cells and plumper histocytic cells [Figure - 5] & [Figure - 6]. Immunostaining for skeletal muscle actin was negative, ruling out a rhabdomyosarcoma. There were no lipoblasts. Other features similar to the previ ous case were present. No syncytial pattern or focal whirling was noted to suggest meningeal origin. Epithelial membrane antigen (EMA) was negative.

DISCUSSION

Malignant fibrous histiocytoma, in extracranial locations, is the most common soft tissue sarcoma in adults,[8],[16] the most common sites being the retroperitoneum and the deep soft tissue of the extremities.

Primary MFH of the CNS is uncommon. In a review in 1998, Akimoto et al reported one case and described 17 previously reported cases.[15] In both our cases there was no evidence of a primary tumor elsewhere. MFH elsewhere with brain secondaries usually occurs in old age while primary brain MFH occurs in relatively younger patients.[15],[16] Cerebral MFH usually involves the parietal, frontal or temporal lobes, whereas in one of our patients the occipital lobe was involved. The lesion in this patient possibly had a meningeal origin with secondary involvement of the overlying bone and scalp and infiltration of the underlying brain.

Immunohistochemistry has provided evidence that these tumors are not derived from cells of monocytic or macrophage lineage but rather from fibroblasts.[17] In case no. 2 we had performed an immunostain for skeletal muscle actin which was negative, excluding a rhabdomyosarcoma.

Plain roentgenograms in MFH involving bone show a poorly circumscribed lytic lesion with areas of calcification while tomograms reveal subtle permeative radiolucent changes extending beyond the poorly demarcated central area of radiolucency. Angiography shows an extensive neovascular response while isotope studies reveal increased uptake beyond the tumor margin. The differential diagnosis includes cystic gliomas, glioblastoma, meningioma, abscess, metastasis and tuberculomas.[8] MRI findings of an intracranial MFH secondary to an extracranial primary lesion have been described.[18] Here, a cystic lesion with a ring-shaped tumor rim of decreasing signal intensity in T₂-weighted image was seen. MRI is superior to CT in demonstrating tumor extent and edema.

The treatment for MFH has been described as a combination of radical excision, radiotherapy and chemotherapy. However, MFH of the brain has always been a gloomy prospect with a relentless course leading to death within the 1st year after surgery.[1] Radical removal in case No.1 would have been extremely formidable due to the involvement of more than one venous sinus converging onto torcular Herophili. The hazards associated with interruption or diversion of venous sinus flow and reconstruction of the torcular Herophili in an attempt to achieve complete resection of a peritorcular malignant tumor seem unwarranted.[19]

REFERENCES

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