PMC5711767_01
(A) Focal increased FDG uptake [maximum standard uptake value (SUV) of 3.8] in the larynx noted on axial fused PET/CT image (blue arrow) corresponds to a (B) soft tissue mass (3.3 cm x 1.7 cm x 2.2 cm) in the posterior cricoid cartilage on contrast-enhanced (CE)-CT scan of the larynx (blue arrow). (C) Posttreatment follow-up FDG-PET/CT acquired 2 months after the end of the radiation therapy showed a decrease of the intensity of uptake; persistence of a very low diffuse uptake (SUV 4.9) is noted probably reflecting post-radiation changes (blue arrow). (D) CE-CT of the neck confirmed decreased size of the residual lesion, now measuring 2.5 cm x 1.0 cm x 2.0 cm (transverse by AP by craniocaudal) (blue arrow) and improved narrowing of the infraglottic airway. (E) Follow-up PET performed 6 months later showed persistent non-specific uptake (SUV 4.7) and (F) essentially unchanged size of the residual soft tissue on non-contrast, low-dose CT of the PET/CT. (G) One-year follow-up PET/CT demonstrated non-specific uptake, and (H) on corresponding non-contrast, low-dose CT of the PET/CT, normal appearance of the cricoid without residual soft tissue was seen.
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F1
No infiltration of adjacent soft tissues, trachea, or arytenoid cartilage was detected, nor was focal calcification observed (Figure 1B, blue arrow). FDG-PET performed 4 days later showed the soft tissue mass involving the posterior half of the cricoid cartilage with increased FDG uptake [maximum standard uptake value (SUV): 3.8] (Figure 1A, blue arrow). Serial follow-up imaging studies showed stepwise resolution (Figure 1C-H, arrows).
Laryngoscopy confirmed the diffuse enlargement of the cricoid cartilage with circumferential subglottic narrowing. (A) The epiglottis (black asterisk), arytenoid cartilages (white arrow heads), and enlarged cricoid cartilage (white arrow). (B) A magnified view of the enlarged cricoid cartilage (white arrow) and arytenoid cartilages (white arrow heads).
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F2
The next day, laryngoscopy confirmed the diffuse enlargement of the cricoid cartilage with circumferential subglottic narrowing (Figure 2). Figure 2A shows the epiglottis, arytenoid cartilage, and enlarged cricoid cartilage. Figure 2B shows a magnified view of the enlarged cricoid cartilage.
CT-guided biopsy of the mass in the cricoid cartilage.
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F3
Since an attempted endoscopic biopsy was not diagnostic, a CT-guided biopsy was obtained four weeks later (Figure 3).
Microscopic pictures of the plasmacytoma. (A) The tumor is entirely composed of plasma cells, some showing the typical perinuclear clearing associated with Golgi apparatus (arrow), H&E, 600x. (B) Immunostain for CD138 shows positive (golden brown) staining in the tumor (200x). (C) Immunostains for lambda and (D) kappa light chains show a significant difference in staining intensity between kappa and lambda chains in favor of lambda chains (200x) demonstrating that the tumor is lambda-restricted.
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F4
Histologically, the tumor was entirely composed of plasma cells, some of which showed the typical perinuclear clearing associated with the Golgi apparatus (Figure 4A, arrow). CD138 (Figure 4B) and stains for immunoglobulin lambda (Figure 4C) and kappa (Figure 4D) in favor of lambda chains, demonstrating that the tumor is lambda light chain restricted. Complete lack of CD20 expression excluded an aggressive B-cell lymphoma.