A 71-year-old man presented to the ophthalmology clinic with a 2-week history of blepharoptosis in the right eye (Fig. 1). His medical history included diabetes mellitus, atrial fibrillation, and hyperlipidemia. He had also undergone a partial colectomy for the removal of a sigmoid tumor, followed by chemotherapy and right nephroureterectomy due to renal cell carcinoma, 9 years ago. Six months before presentation, multiple lung nodules with pleural effusion were detected, and biopsy revealed anthracitic pigmentation.
On ocular examination, the best-corrected visual acuity was 20/25 in the right and 20/30 in the left eye. Margin reflex distance was − 5.0 and 3.0 mm in the right and left eyes, respectively (Fig. 1). Both pupils were isocoric and round, and the pupillary light reflex was normal. An alternate prism cover test revealed 16 prism diopters of left hypotropia in the primary gaze both at a distance and near fixation. Ductions and versions revealed limitations of supraduction (grade − 3) and infraduction (grade − 2) in the right eye, whereas no exophthalmos was noted in the left eye (Fig. 1).
Enhanced orbital magnetic resonance imaging (MRI) revealed an extraconal, well-defined, and enhancing round mass measuring 3.5 cm in maximal diameter arising from the superior rectus muscle (Fig. 1). The mass showed spontaneous enhancement without evidence of bone invasion or destruction.
Under general anesthesia, we performed superior orbitotomy and biopsy of the extraconal orbital mass. Microscopic pathology revealed the presence of spindle cells, epithelioid cells, and frequent pleomorphic cells, including multinucleated giant cells in fibrotic stroma. Immunohistochemical (IHC) staining showed that some spindle and pleomorphic cells were positive for smooth muscle actin (SMA) and desmin, consistent with a malignant smooth muscle neoplasm, and specifically, leiomyosarcoma (Fig. 2). Additional excisional biopsy of the right abdominal wall mass was performed, and the abdominal wall mass was found to be composed of histologically similar cells with severe central fibrosis. The differentiated spindle cells were also positive for SMA and desmin. The tumor was diagnosed as a pleomorphic leiomyosarcoma.
Whole-exome sequencing was performed on the formalin-fixed paraffin-embedded tumor tissue using the Illumina HiSeq 2500 platform, with an average read length of 2 × 101 bp, according to manufacturer instructions (Macrogen Inc., Seoul, Republic of Korea). Target region bases were sequenced for each sample using the HiSeq 2500 system (Illumina, San Diego, CA), achieving an average coverage depth of 715× (Macrogen Inc., Seoul, Republic of Korea). After applying a similar filtering method to the exome sequencing data, as done in a previous study,6 we observed 107 somatic mutations involving 103 genes (Supplementary table 1). Most mutations in each tumor specimen represented single-nucleotide variations (47%), whereas multi-nucleotide variation accounted for 43%, deletions for 6%, and insertions for 5% of the mutations (Table 1). In comparison to previous studies, fewer mutations were identified using similar variant calling.6 TP53, MDM2, CDKN2A, KIT, ATRX, RB1 and MED12 somatic mutations, which were frequently detected in other leiomyosarcoma NGS studies, were not identified.7
Table 1
Frequency of somatic mutations in pleomorphic leiomyosarcoma
Somatic mutations
|
Frequency
|
Average coverage
|
110.91
|
Covered ≥ 4 reads (%)
|
99.68
|
Total variant counta
|
107
|
Single nucleotide variants (%)
|
50 (47)
|
Multi-nucleotide variants (%)
|
46 (43)
|
Deletions (%)
|
6 (6)
|
Insertions (%)
|
5 (5)
|
Mutations per Mbb
|
1.43
|
TMB = 107 variants/74.569526 Mbases = 1.43 MUT/Mb |
a Total variant count comprises all variants located in positions with a minimum coverage of six reads and the mutated allele present in at least 2% of the reads, remaining after filtering the sequencing data against 9,977 East Asian individuals from The Genome Aggregation Database v2.1.1, 4,327 East Asian individuals from The Exome Aggregation Consortium v0.3.1, and 1950 in-house control exomes from Korean individuals. |
b Mutations per Mb was calculated by dividing the total number of somatic mutations by the total number of called nucleotide positions (≥ 6 reads) |
The final diagnosis was metastatic leiomyosarcoma, and the patient received one cycle of systemic chemotherapy (adriamycin). The patient received hospice care because of his worsening condition but died due to respiratory failure one month after diagnosis.