A 37-year-old married male patient was admitted to our hospital on May 10, 2015, with a subcutaneous mass on the left frontal vertex that had been present for 1 month and was gradually enlarging. Examination revealed a subcutaneous mass approximately 4 cm x 5 cm on the left frontal vertex. The mass was pliable, non-tender upon palpation, with a clear texture, well-defined borders, and no tenderness, elevated about 0.7 cm above the normal skin margin.
CT indicated local lytic changes in the left frontal bone, with spindle-shaped hypo-to isodense shadows seen on the inner and outer aspects of the skull. The partial brain tissue was slightly compressed and shifted inward, with uneven density within and a CT value of about 38 HU. Uneven enhancement was observed at the edges.
MRI revealed a spindle-shaped lesion with equal T1 and long T2 signals in the left frontal vertex bone, measuring approximately 2.2 cm x 3.5 cm x 4.0 cm, growing centered on the skull bone, with corresponding bone absorption and thinning. Bone destruction within presented as uneven low signals and abnormal uneven enhancement was noted at that location after contrast enhancement, with significant enhancement on delayed scanning. The adjacent brain parenchyma was slightly compressed and shifted inward (Fig. 1).
During surgery, a mass in the left frontal area was observed to have a fish-flesh appearance, firm texture, and no significant adhesion to the scalp. An intraoperative frozen section examination was performed. After fully exposing the extracranial tumor, the skull was drilled, and the bone was bitten along the tumor. A circular incision was made in the dura mater. Due to the lack of adhesion between the tumor and the brain, the entire tumor was removed (Fig. 2). Following the intraoperative frozen section examination, which suggested a malignant tumor, the scope was expanded, and approximately 2 cm of surrounding tissue was removed. A range of about 8 cm x 8 cm of normal skull and dura mater was excised, and a phase-one artificial dura mater and titanium mesh repair were performed.
The pathological diagnosis of leiomyosarcoma was made based on the presence of spindle-shaped and round-like irregularly arranged cells within the tumor, with abnormally enlarged nuclei that were deeply stained and significantly atypical. A few vacuolated cells were seen, with abundant acidophilic cytoplasm and visible mitosis, diffusely forming plaques and some interstitial mucoid degeneration.
Immunohistochemistry results showed silver staining (+), B-cell lymphoma-2 (Bcl-2, +), CD34 (+), FLI-1 (+), FN (+), SMA (+), CD68 (scattered), and Ki-67 (30%). The specimen's margins were normal tissue (Fig. 3), which observed tumor cells arranged in irregular spindle shapes, with enlarged nuclei and some cells displaying a vacuolar appearance.
The patient was followed up 9 days after discharge. As the tumor was completely excised and was not sensitive to radiotherapy and chemotherapy, no such treatments were administered. Routine follow-ups for 2 years and 3 months until August 2017 showed no recurrence, and PET-CT scans during this period did not reveal any recurrence or distant metastasis. At 2 years and 4 months postoperatively, a subcutaneous mass appeared on the left frontotemporal vertex, considered to be a recurrence of the leiomyosarcoma.
The patient was admitted again on September 27, 2017, due to a lump found on the left frontotemporal vertex for 20 days. Examination revealed the original surgical scar on the left frontotemporal vertex and a subcutaneous mass approximately 3 cm in diameter, with a pliable texture, no tenderness upon touch, clear boundaries, no redness or skin ulceration, no noticeable movement, and elevated about 0.5 cm above the normal skin margin. No vascular murmur was heard within the mass. Enlarged lymph nodes were palpable on both sides of the neck, with the largest being about 3 cm in diameter.
CT indicated an absence of bone substance in the left frontotemporal vertex, with a broad-based segment of low-density shadow visible, clear boundaries, measuring approximately 3.2 cm × 1.3 cm, and a CT value of about 39 HU. MRI showed a mass and post-surgical change in the left frontal vertex, with an irregular abnormal lesion seen in the inner table of the left parietal bone, presenting as equal T1 and slightly long T2 signals, measuring about 3.5 cm × 1.6 cm × 3.5 cm in size, with uneven enhancement after contrast, and significant mass effect (Fig. 4).
During the surgery, a mass of approximately 3 cm × 4 cm was observed attached to the three-dimensional titanium mesh on the left frontal vertex, with no clear demarcation from the surrounding tissue. The mass was removed in sections, and after removing the titanium mesh, a mass with a diameter of 4 cm was seen on the left parietal vertex. The excised mass had a fish-flesh appearance and clear demarcation. The artificial dura mater, tumor tissue, and affected skull in that area were excised. The tumor originated from the dura mater at the vertex, and an additional 3 cm of skull, dura mater, periosteum, and subcutaneous tissue towards the vertex were removed. Towards the frontotemporal area, 4 cm away from the tumor, proliferative tissue, artificial dura mater, brain tissue, and skull were excised, along with a skin flap measuring 2 cm × 5 cm at the tumor site. The surgical procedure involved a phase-one repair with artificial dura mater and titanium mesh.
The secondary pathological diagnosis still showed leiomyosarcoma (WHO Grade III). Within the tumor, spindle-shaped and round-like irregularly arranged cells were observed, with nuclei that were deeply stained and enlarged. HE showed significant pleomorphism, accompanied by a few vacuolated cells, and conspicuous mitotic figures diffusely distributed in sheets, with some interstitial mucoid degeneration (Fig. 5). Immunohistochemistry studies revealed silver immersion staining (+) and SMA (+). No tumors were found in the surrounding tissues, and neck lymph node needle aspiration cytology biopsy showed no tumor cells.
The patient was discharged 10 days after surgery. Considering the recurrence of leiomyosarcoma without metastasis, no radiotherapy or chemotherapy was administered before or after the surgery. The patient regularly returned for check-ups after discharge, and as of June 1, 2020, had been followed up for over 2 years and 8 months, with no significant complications arising, and follow-up is ongoing.