Panacea Journal of Medical Sciences

Study setting

Department of Neurosurgery, S.M.S. Medical College and Hospital, Jaipur, Rajasthan.

Inclusion criteria

Skull tumor patients presenting in the Department of Neurosurgery during academic year 2022-2023.

Study design

Cross sectional study.

Study type

Descriptive observational study.

Sample size

Patients with skull tumor.

The hematoxylin and eosin-stained slides were recovered from the Department of Pathology and diagnoses were reviewed. The clinical parameters such as age, sex of patient and location of tumor were distinguished.

Osteoma

Osteomas are usually benign and slow growing bony tumors, observed in young adult males. Osteomas are non-cancerous slowly growing fibrous tumors having litlle osseous spicules implanted in proliferating connective tissues. The most frequent location is the fronto-ethmoidal region ^[4] with peak incidence around age of 10-30 years. These are uaually formed in the outer table of skull. The CT scan of osteoma depicts homogenous, well-defined, sclerotic lesions ([Figure 5]). Osteomas are 100% treatable by surgical methods. Gundewar et al found that 25% of craniofacial osteomas were in the orbit and only 17% in the frontal bone. In our study, we diagnosed 3 osteomas in the frontal bone. Multiple osteomas are usually found in patients of Gardner syndrome, intestinal polyps, desmoids & epidermoid cysts. ^[5], ^[8]

Brown tumor

Brown tumor is a benign osseous lesion linked with hyperparathyroidism. It is commonly seen in medullary shaft of long bones & is multifocal or solitary. Khalatbari et al. reported 3 cases of brown tumors of the anterior base of skull as early presentation of true normo-calcemic primary hyper parathyroidism. In the CT scan, they show as well-defined, lytic, uni or multilocular lesions which activate small reactive bone formation. ^[9]

In this study, we had a 52-year-old male with a swelling on forehead and complaint of frequent headaches since one year. Patient was investigated thoroughly and MRI with NCCT head was done, which depicted expansile lobulated lesion of frontal bone with erosion of outer and inner table of skull and expansion of bone leading to mass effect on bi frontal lobes ([Figure 6]). USG neck showed characteristics of right sided parathyroid mass. Histopathology was suggestive of a giant cell lesion. As the patient was a case of hyperparathyroidism, Brown tumor diagnosis was suspected.

Fibrous dysplasia

In our study, we found three cases of Fibrous dysplasia. A male aged 20 years, presented with painless swelling over left frontal bone for 3 years. Another patient, a 16-year-old male presented with abnormal swelling over head in frontal region for 4 years and other patient was a 28 year old female who presented with painless swelling over the head involving frontal, parietal and temporal region since last 5 years. In all the patients, thickening of involved bone with expansion was seen with no remnant of any adjacent soft tissue ([Figure 7]). Fibrous dysplasia is mainly identified by immature weak woven bone replacing the normal bone. ^[8] It is generally seen in childhood and younger age groups (10-30 years). It is usually asymptomatic and painless but because of mass enhancement sometimes, it may present with symptoms and is found in frontal or temporal bone. In a study done by Leeds, ^[10] 46 patients having Fibrous dysplasia were studied and most common symptom was asymmetrical skull & facial bones. Although the cause is not evident, the molecular studies suggest a mutation in the Gsα subunit and activation of c-fos & other proto-oncogenes. Complete excision of tumor was done followed by Cranioplasty. ^[10]

Hemangioma

Primary intraosseous cavernous hemangiomas (PICHs) are rare bone tumors. Skull hemangiomas are found in the vault, generally, the frontal bone and predominantly seen in patients in their fourth and fifth decades. Different clinical presentations can be seen in accordance with the involved site Invasion of orbit leads to proptosis and impaired vision. Temporal bone involvement presents as paralysis of facial nerve, oral commissure twitching, pulsatile tinnitus and loss of hearing. Patients may also develop epidural hematoma or subarachnoid hemorrhage. The most common clinical feature was a painful or painless solid swelling in the skull ([Figure 8]). Patients can complain of frequent headaches or dizziness.^[11] In our series, one case was seen involving the frontal bone who presented with symptoms of painless swelling overhead since last 5 years. The management for skull PICH is total resection with proper normal bone margins to reduce the bleeding risk. Relapse is rare when adequate safety margins are secured. Other treatment option is curettage then later re canalization and irradiation, to reduce the volume of tumor. It has shown symptomatic improvement, but with radiation-induced carcinoma risk. ^[11]

Ewing sarcoma/Peripheral primitive neuroectodermal tumor (ES)

ES is a malignant tumor showing variable degree of neuroectodermal differentiation. It is specified by recurrent balanced translocations of the EWSR1 gene on chromosome 22. It presents in patients of younger age group (<20 years) and found in the diaphysis of long bones. The skull and vertebrae can be involved too. It may arise primarily from the dura, to be misidentified as meningioma on radio images. Histologically, ES is made up of malignant small round cell sheets with scanty cytoplasm containing glycogen, which leads to cytoplasmic clearing of tumor cells. Homer-Wright rosettes can be seen which indicates neuroectodermal differentiation. Distinguishing feature can be diffuse strong membranous positivity for CD99 (MIC2 gene product). On CT imaging, an onion-peel setting with layers of bone mottling and erosion along with new bone formation is observed ([Figure 9]). Surgical removal of the tumor is advised followed by radio and chemotherapy. Prognosis is usually poor to moderate, depending on condition and followed treatment. ^[12]

Metastases

Metastases to the calvarium is commonly seen in cancers. Most commonly brain metastases is observed in breast cancer followed by lung, prostate and lymphoma. Brain metastases are divided into 2 anatomical classes which present distinctive clinical features. One group is calvaria metastasis, generally asymptomatic or may lead to dural invasion, dural sinus occlusion or cosmetic issues. The second group is skull-base metastasis, which presents with cranial-nerve involvement leading to devastating symptoms. A high index of suspicion based on new-onset cranial nerve deficit or craniofacial pain in a cancer patient is important for early diagnosis and prompt management. Magnetic resonance imaging is the primary diagnostic tool. Skull metastasis is a focal lesion with low intensity signal on T1-weighted images. Enhanced T1-weighted images with fat-suppression show tumor, dural infiltration and cranial nerve involvements. Irradiation is the effective and primary treatment for skull metastases. Chemotherapy or hormonal therapy can be used depending on sensitivity of tumors. Bone resorption inhibitory drugs prescribed in systemic therapy are found to be suitable for prevention of symptomatic skull metastasis.

Surgery is done in few patients who require immediate decompression, cosmetic recovery, or have proven histological diagnosis. ^[13] According to literature, metastases from thyroid is not so frequent. ^[12] Most common metastases from the thyroid cancer is follicular sub type. ^[14]

A 50-year-old female patient observed a swelling on her right occipital region since 1 year. Patient was evaluated and diagnosed as a case of right occipital space occupying lesion with extracranial extension. NCCT head revealed soft tissue density with calcific foci causing destruction of occipital bone on the right side along with intracranial extension. Patient underwent right occipital craniotomy with wide local excision. Histopathology showed metastases from follicular thyroid cancer. The literature points out that these tumors are more common in females. The most favourable site for these tumors is midline of the frontal and parietooccipital region. Y Nagamine (1985) et al. ^[15] in their study found that the incidence of skull metastasis from thyroid cancer was higher among women. The most frequent histopathological presentation was follicular adeno carcinoma. Such lesions were morphologically well differentiated, with little pleomorphism and atypism but detailed examination showed infiltration into the vascular lumen or capsule. The mean survival time in these patients was 4.5 years from the time of diagnosis.

A 60-year-old female developed a painless swelling on forehead since 2 months. CT head depicted destructive soft tissue density lesion along with calcification and erosion of frontal bone, glabella leading to metastases (Image 6&7). On work up for primary, HRCT thorax revealed a malignant mass with spiculated margins in left upper lobe of lung along with calcified foci and multiple enlarged lymph nodes in pre or para tracheal area. USG guided FNAC of frontal area mass depicted poorly differentiated malignant neoplastic cells. Histopathological reports suggested metastases from lung cancer. Lung cancer cells can spread via bloodstream or lymphatics to the brain. Komatsu et al. ^[16] investigated 70 patients with brain metastases from histologically confirmed lung cancer. Turner et al. ^[17] encountered a case of lung cancer metastases showing solitary skull lesions. D’Antonio et al. ^[18] reported a review demonstrating the newer advancements in therapeutic management of bone and brain metastases in lung carcinomas. Pain is the first symptom of lung cancer with bone metastases in 80% of patients. ^[19] Patients with osseous metastases complain of pain at some point with wide variation in pattern and severity. ^[20] Many factors are implicated in the pain of osseous metastases but a significant portion of the pain seems to be related to osteoclastic bone resorption. Surgery, irradiation, stereo-tactic resection and chemotherapy have proven beneficial to treat such patients.