A 52-year-old female with a background history of hypertension was referred to our center by a physician at a private clinic for a large right frontal swelling. According to the patient, she first noticed the swelling 2 years back, and it was initially the size of a marble (1 cm). The swelling gradually increased in size. It would occasionally cause itchiness on the overlying skin, and caused some discomfort as it grew bigger, but otherwise the swelling was painless. She denied experiencing a change of color or temperature over the swelling, and she denied ulceration and/or discharge from the swelling. The patient did not have any headaches, blurring of vision, nausea, and seizure. As the swelling had never caused her any problems, she only agreed for further workup after her physician coaxed her during her follow-up for hypertension.
On examination, there was an obvious single lump involving most of the right side of the patient's forehead, measuring 8 cm x 8 cm. The skin overlying it was slightly stretched, but otherwise normal. We could not see any sinuses, ulcerations, nodules, or even sinuses. It had the same temperature as the rest of her face. The swelling had diffuse borders and was firm-to-hard to the touch. It was not compressible or indentable, and was nontender. The swelling was not attached to the skin, but it was not mobile; it was most likely attached to the bone. Neurological examination did not yield any abnormality.
Our initial impression was a dermoid cyst, a lipoma, or an osteoma. In view of her age, we were also considering a malignant bony tumor. The patient was admitted for further workup. Blood investigations did not show any abnormality, with normal full blood count, renal function test, and serum calcium. The erythrocyte sedimentation rate (ESR) was not raised, at 15 mm in the 1st h. Plain and contrasted computed tomography (CT) imaging was done, revealing that the swelling was a lytic bone lesion, with a punched-out appearance of the affected bone. On the outer surface of the cranium, the lesion extended beyond the bony defect and sloped off at the edges. The purely extra-axial lesion was isodense with brain tissue, and only the inner surface took up contrast, likely due to the involvement of the dura [Figure 1].
From the CT imaging, our impression was a right frontal intraosseous meningioma. We counseled the patient for surgery, with the aim for cytoreduction and histological diagnosis. We designed a question mark flap to encompass the right fronto-temporo-parietal regions, and as one of our differential diagnoses was an intraosseous meningioma, we also dissected the patient's neck in a curvilinear manner at the level of C4/C5 to expose the internal and external right carotid arteries in the event that we needed a proximal control for hemorrhage.
We had initially planned to raise the scalp as two layers, and to harvest the pericranium in the event that we needed to do a fascia duraplasty. However, the pericranium had eroded. The lesion was noted to be smooth and had a firm consistency, with a well-demarcated margin along the punched-out bone edge. We could not see any vessels feeding into the swelling. A craniotomy was made 1.5 cm away from the margin, but the dura, tightly adherent to the inner cranial surface, was circumferentially torn during bone cutting. There was not much bleeding during the craniectomy. We noted a single pedicle under the inner surface of the bone: The enlarged right middle meningeal artery (MMA). After ligation using sutures, the MMA was severed, and the lesion, along with a rim of bone, was excised en bloc. The brain surface was indented, but otherwise the arachnoid layer was intact, and we did not see any abnormality on the brain surface. The dura defect was closed using an artificial tissue dura, and we proceeded with primary closure of the scalp [Figure 2].
The lesion was cut in half, and we noted that under the firm, fibrous capsule, the lesion was whitish and soft-to-firm inconsistency. In view of the scalp tissue and dura involvement, we suspected a calvarial metastatic tumor.
The patient recovered well-postoperatively. She did not have any neurological deficit, and she did not develop any seizures. We planned for a full workup for a primary source; however, the histopathological report came back as extensive areas of caseous necrosis surrounded by a collection of epithelioid histiocytes, lymphocytes, and several Langerhans-type giant cells forming granulomas. Ziehl-Nielsen stain for acid-fast bacilli was negative. The granuloma was also seen within the bone. The histopathological diagnosis was a caseating granulomatous inflammation, highly suggestive of tuberculosis.
The patient was then subjected to anti-tuberculosis treatment, planned to complete a 1 year therapy. She was also planned for a titanium mesh cranioplasty during subsequent follow-ups. The patient was well at the time of writing, and contact screening for tuberculosis was negative.