case_images: PMC8474338_01
case_images: Photomicrographs of a hematoxylin and eosin-stained tissue section revealing: (a) tumor
  infiltration into the surrounding tissue (4x field of view). (b) Palisading of tumor
  cells (10x field of view). (c) Tumor showing solid growth pattern and mitotic figures
  (4x, 20x field of view).
case_images: 10.1177_2050313X211048041-fig1.jpg
case_images: PMC8474338_01_10.1177_2050313X211048041-fig1.jpg
case_images: fig1-2050313X211048041
case_images: Pathological findings revealed malignant atypical cells and stroma infiltrations (Figure 1(a)); however, because the tissue had a palisading pattern similar to BCA (Figure 1(b)), we diagnosed the tumor as BCAC. The tumor had a solid-type structure, and the tumor cells with mitosis (Figure 1(c)) were significantly fragile, making it difficult to judge the surgical margin.
case_images: Computed tomography (CT) and intraoperative view in 2021: (a) paranasal CT finding in
  2021: CT revealing the tumor in the left maxillary sinus and orbital floor and (b)
  intraoperative view showing partial maxillary resection using a Weber-Ferguson incision;
  the tumor infiltrates the orbit (white arrow).
case_images: 10.1177_2050313X211048041-fig2.jpg
case_images: PMC8474338_01_10.1177_2050313X211048041-fig2.jpg
case_images: fig2-2050313X211048041
case_images: In 2021, since a tumor recurred in the nasal septum and maxillary sinus with bleeding, paranasal computed tomography with contrast effect showed the tumor in the left maxillary sinus and its recurrence in the orbital floor (Figure 2(a)). The tumor infiltrated the orbital floor bone (white arrow), as in the last operation (Figure 2(b)).
case_images: Immunohistochemical findings: (a) hematoxylin and eosin-stained sections (20x field of
  view). (b) Ki-67 labeling index is 25% (20x field of view). (c) Epidermal growth factor
  receptor is positive in the tumor cell membrane (20x field of view). (d) p53 is negative
  in the tumor cells (20x field of view). (e) B-cell lymphoma-2 is negative in the tumor
  cells (20x field of view).
case_images: 10.1177_2050313X211048041-fig3.jpg
case_images: PMC8474338_01_10.1177_2050313X211048041-fig3.jpg
case_images: fig3-2050313X211048041
case_images: The histopathological findings showed malignant atypical cells and stroma infiltrations (Figure 3(a)), and the Ki-67 labeling index was 25% (Figure 3(b)). Tumor cell membranes were diffusive and positive for epidermal growth factor receptor (EGFR) (Figure 3(c)). The tumor cells were negative for p53 (Figure 3(d)) and B-cell lymphoma-2 (bcl-2) (Figure 3(e)).