Sarcomas in Teachers Using Three-Dimensional Printers: A Report of Three Patients and Literature Review

Abstract

Background: While low-cost, small-scale, desktop three-dimensional (3D) printers are gaining popularity in the education sector, some studies have reported harmful emissions of particles and volatile organic compounds during the fused deposition modeling (FDM) process, posing a potential health risk. Sarcomas are rare tumors, constituting a group of diverse rare malignant tumors. While some genetic and environmental factors contribute to the development of sarcomas, most cases are idiopathic and sporadic.

Methods: We secured the medical records and statements about work environment from teachers diagnosed with sarcomas after frequent use of 3D printers in high schools, reviewed the cases, and described them in narrative format. Furthermore, popularization of FDM 3D printers, worrisome emissions released during the printing process, and related precautions and countermeasures were discussed through literature review.

Results: Exceptionally, the cases of sarcomas, such as Ewing's sarcoma, malignant peripheral nerve sheath tumor, and well-differentiated liposarcoma, arose in a common specific condition. All the teachers regularly operated 3D printers in poorly ventilated spaces for at least 2 years. They had no past or family history of relevant diseases.

Conclusions: We first reported three cases of sarcoma in teachers who used 3D printers in poorly ventilated conditions. Although a relationship between the use of 3D printers and the development of sarcomas has not been determined yet, it is important to come up with measures to protect teachers and students using 3D printers from the potential hazard.

Keywords: Sarcoma; School teachers; Three-dimensional printing; Ultrafine particles; Volatile organic compounds.

Fig. 1. Workspace for three-dimensional printing. Patient 1 operated printers in a room of approximately 3.3 × 6.6 m² with only a very small window, an entrance, and no air purifiers.

Fig. 2. Patient 1. T1-weighted fast spin-echo coronal (A), fat-suppressed T2-weighted fast spin-echo axial (B), and fat-suppressed contrast-enhanced T1-weighted fast spin-echo sagittal (C) magnetic resonance images of the sacrum showed an enhanced main lesion (arrows) involving the right gluteus maximus, gemelli, ischiococcygeus, and obturator internus, penetrating the right levator ani and puborectalis and infiltrating the perirectal space. Positron emission tomography/computed tomography images revealed ¹⁸F-fluorodeoxy-glucose-avid bone lesions in multiple sites including the left clavicle (D) and right proximal femur (E). Pathology slides of a core-needle biopsy specimen demonstrated a tumorous lesion with necrosis (F), composed of small round cells nests (H&E, × 12.5), and clusters of small round cells (G) with hyperchromatic round to oval nuclei, scant or eosinophilic cytoplasm, and indistinct cytoplasmic membranes (H&E, × 1,000).

Fig. 3. Patient 2. T1-weighted turbo spin-echo sagittal (A), T2-weighted turbo spin-echo axial (B), and contrast-enhanced T1-weighted turbo spin-echo coronal (C) magnetic resonance images of the pelvis showed a large mass (arrows) encasing retroperitoneal neurovascular structures, such as the sacral plexus and iliac vessels, diffusely involving the sacrum. (D) A ^99mTc-hydroxymethylene diphosphonate bone scintigraphy of the whole body revealed increased radionuclide uptake in the skull, sacrum, and right ischium. (E) A histology slide of a core-needle biopsy specimen (H&E, × 12.5) demonstrated a tumorous condition and a diffuse growth pattern with alternation of high- and less-cellular areas and myxoid stroma. (F) In another slide (H&E, × 1,000), vague tumor cells fascicles with hyperchromatic, oval to elongated nuclei and finely dispersed chromatin, and mild perivascular tumor cell accentuation were identified.

Fig. 4. Patient 3. T1-weighted turbo spin-echo axial (A), fat-suppressed T2-weighted turbo spin-echo axial (B), T1-weighted turbo spin-echo sagittal (C), and fat-suppressed Gadolinium-enhanced T1-weighted turbo spin-echo coronal (D) magnetic resonance images of the thigh showed a huge fatty mass in the right quadriceps femoris with thin septa. Pathology slides of an excision specimen demonstrated a tumorous lesion (E) with variably thickened fibrous bands or septa between lobules of adipocytes in some areas (H&E, × 12.5) and a few atypical adipocytes and stromal cells (F) (H&E, × 500).