PMC9155930_01
The CT scan showing a right parotid gland lesion in 2017.
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The CT scan showed a right parotid gland lesion (Figure 1).
The histopathology with hematoxylin and eosin (H&E) stain showing a multifocal acinic cell carcinoma of the right parotid gland in 2017. (a) Low power showing lymphoid-rich stroma with lymphoid follicles and prominent germinal centers within tumor. (b) Medium power showing tumor with acini and granular cytoplasm. (c) High power x60 showing the basophilic granular cytoplasm (zymogen granules of neoplastic serous acini).
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T1, N1, M0 involving both deep and superficial lobes, with a margin of 1 mm, and 1 intraparotid lymph node was involved (Figure 2). Then, she was admitted electively to our tertiary care hospital.
The PET scan in November 2017. (a)-(c) There is mild background level FDG avidity (SUVmax 2.2) in the region of the right parotid. This uptake is most likely postsurgical. Also, there is mild FDG avidity (SUVmax 1.7) within a few prominent (up to 11 mm short axis) right upper cervical (levels II-III) lymph nodes. The exact etiology remains indeterminate (i.e., whether could be malignant or reactive due to her recent surgery). Also, small volume lymph nodes (measuring up to 8 mm short axis) are present in the left upper cervical/level II region, with minimal FDG uptake, as this is a common site for reactive lymphadenopathy. On the other hand, there are additional small volume bilateral submental and submandibular lymph nodes (up to 6 mm short axis) with no definite FDG uptake. Uptake of the tracer elsewhere is within physiological limits.
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This uptake is most likely postsurgical (Figure 3).
The PET scan in November 2018. The study was compared with the previous scan of November 20, 2017. Overall, the study ((a)-(c)) is stable without any evidence of local recurrence or distant metastasis.
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Overall, the study is stable without any evidence of local recurrence or distant metastasis (Figure 4).
The CT scan showing a left deep parotid gland lesion in 2020.
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The CT scan showed left deep parotid gland lesion (Figure 5).
The PET scan in August 2020. The study showed an interval anatomic increase in size and metabolic progression in the known suspicious left deep parotid lesion ((a)-(c)). Measure approximately 2.0 x 1.9 x 2.2 cm in anteroposterior, transverse, and craniocaudal dimensions, respectively, with standard uptake value max (SUVmax) of 3.2. The SUVmax was previously 2.2. On the other hand, there is a more prominent left infraparotid subcentimeter node showing mild fluorodeoxyglucose (FDG) uptake. SUVmax 1.2 is indeterminate. Moreover, an anatomically stable mild FDG-avid left jugulodigastric subcentimeter node with SUVmax up to 1.4 and right supraclavicular node (SUVmax 1.0) are nonspecific, likely reactive. No other size significant FDG-avid cervical lymphadenopathy.
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Measure approximately 2.0 x 1.9 x 2.2 cm in anteroposterior, transverse, and craniocaudal dimensions, respectively, with standard uptake value max (SUVmax) of 3.2 (Figure 6).
The histopathology with hematoxylin and eosin (H&E) stain showing acinic cell carcinoma with lymphoid background of the left parotid gland in 2020. (a) Low power showing lymphoid-rich stroma. (b) Medium power showing tumor with acini and granular cytoplasm. (c) High power x60 showing the basophilic granular cytoplasm (zymogen granules of neoplastic serous acini). The same tumor occurred metachronously in the left parotid gland.
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The histopathology with periodic acid-Schiff plus diastase (PASD) stain showing acinic cell carcinoma of the left parotid gland in 2020. (a) Periodic acid-Schiff plus diastase (PASD) stain low power showing acinic cell carcinoma cells with PASD-positive granular cytoplasm. (b) Periodic acid-Schiff plus diastase (PASD) stain high power showing PAS + diastase resistant granules in Acinic cells.
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Symptoms, investigations, radiotherapy course, and surgeries.
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A left total parotidectomy and left neck dissection (Figure 9) was done in December, 2020.
The PET scan in January 2022. The study ((a)-(c)) was compared with previous studies. The upper and lower cervical lymph nodes are showing mild FDG avidity with SUVmax of 1.8. However, there is no change morphologically, and it is most likely reactive. On the other hand, physiological radiotracer distribution is seen in the brain and there are no new suspicious FDG-avid lesions seen otherwise.
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Since then, the patient has been following regularly in our hospital for any signs of recurrence, and the latest PET-CT of the patient was done in January, 2022 (Figure 10).