Skull Invaders: When Surgical Pathology and Neuropathology Worlds Collide

Abstract

Skull and dura serve as effective barriers to penetration by most tumors, often preventing masses originating intracranially from extending into the contiguous bone and soft tissues, or those arising in head and neck regions from extending into the dura and brain tissue. We review our 15-year experience with extracranial tumors that had sufficiently invaded adjacent skull, dura, or brain from the "outside-in" to require a neurosurgeon to participate in the surgical resection and discuss our 40 cases in context with the literature. Sinonasal-origin tumors (n = 17) and cutaneous tumors (n = 10) were the most frequent skull-invaders. Most of the cutaneous tumor types were squamous cellcarcinomas (n = 9); diverse sinonasal-origin types included 4 squamous cell carcinomas, 4 adenoid cystic carcinomas, 2 sinonasal undifferentiated carcinomas, 2 sinonasal adenocarcinomas, and single examples each of sinonasal-origin hemangiopericytoma, solitary fibrous tumor, melanoma, mucocele, and teratocarcinoma. There were 9olfactory neuroblastomas, and middle ear-origin basal cell carcinoma,recurrent glomus jugulare, and orbital malignant hidradenoma were also seen. Unique tumors included a cutaneous cylindroma invasive of skull convexity occurring in familial cylindromatosis and a ganglioneuroma of the middle ear with massive bilateral skull base extension. Convexity dural spread, a seldom-reported pattern of dissemination, was seen in 1 olfactory neuroblastoma and 1 adenoid cystic carcinoma. The ability to show skull/dural invasion did not correlate with specific histopathologic features; even benign tumor types can show skull/dural penetration.

Recurrent squamous cell carcinoma with intracranial invasion of the dura mater after Mohs surgery

“…In a retrospective study on cutaneous, sinonasal, and middle ear tumors invading the skull, the most common tumor was cSCC. 4 In this study, most patients with cSCC skull invasion were males aged 53 to 86 years, had the tumor on a skull convexity, and demonstrated moderately differentiated cSCC. 4 Our patient had all of these characteristics.…”

“… 4 In this study, most patients with cSCC skull invasion were males aged 53 to 86 years, had the tumor on a skull convexity, and demonstrated moderately differentiated cSCC. 4 Our patient had all of these characteristics. On further analysis of treatment history, multiple patients with skull-invasive cSCC had a history of multiple excisions/resections before undergoing neurosurgery.…”

“…On further analysis of treatment history, multiple patients with skull-invasive cSCC had a history of multiple excisions/resections before undergoing neurosurgery. 4 If our patient did not present with persistent drainage, negative infectious workup results, or bone fragment recovery during incision and drainage, it is possible that his recurrent SCC would not have been identified until much later. Initial magnetic resonance imaging would have been better than CT if we were highly suspicious of intracranial invasion.…”

Genetic Testing in CYLD Cutaneous Syndrome: An Update

“…Clinical features that should be reported by patients as they are associated with cutaneous malignancy are as follows: tumour ulceration; rapid tumour growth; tumour pain; intermittent bleeding from a tumour, colour change in the surface of the tumour; tethering of the tumour to underlying bone. 26 Invasion through the skull plate has been observed, 27,28 supporting the use of radiological imaging in selected advanced CCS cases preoperatively. Malignant CCS tumours may metastasise to other tissues including the liver, lungs and bones.…”

Cystic sellar salivary gland-like lesions

“…Rare other primary intracranial adenoid cystic carcinomas have been reported of the right frontal lobe [ 21 ], and even in the sella [ 22 ], as well as metastases to the sella by adenoid cystic carcinomas with primary site elsewhere [ 23 , 24 , 25 ]. Even more frequent is invasion of the skull base by salivary gland tumors primary in head and neck regions [ 7 , 15 , 26 , 27 , 28 , 29 ]. The anatomical location and clinical context allow distinction of these latter entities from sellar salivary gland-type tumors.…”