PMC4293552_01
Ultrasonographic (A-C) and operative (D) findings. A 29 x 10-mm heterogeneous isoechoic to hypoechoic mass (A) was noted at the 4th to 5th flexor tendon of the left hand (B, white arrows). There was no increased blood flow in this mass on the color Doppler image (C). Intraoperative findings showed hypertrophied tenosynovium enveloping the flexor tendon and discolored lumbrical muscle involvement (D).
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F1
Ultrasonography revealed a 29 x 10 mm hypoechoic mass at the tendon sheath of the left fourth and fifth flexor digitorum profundus (FDP) (Fig. 1A-C). Upon surgery, inflammatory hypertrophied tenosynovial tissue enveloping the flexor tendon sheaths of the third to fifth fingers, and necrotized lumbrical muscle of the third to fifth fingers were observed (Fig. 1D).
(A) Diffuse infiltration of atypical lymphoid cells with geographic necrosis was noted (H&E, x12). (B) Atypical lymphocytes infiltrated the soft tissue (H&E, x200). Immunohistochemical staining showing cells in the mass were CD-20 negative (C, x200), CD-3 positive (D, x200), and CD-5 positive (E, x200). The lesion was positive for Epstein-Barr virus encoded RNA based on in situ hybridization (F, x200).
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F2
Histopathologic examination showed diffuse infiltrative atypical cells with geographic necrosis (Fig. 2A and 2B). Immunohistochemical staining for CD20 was negative (Fig. 2C), and CD56, CD3, and Epstein-Barr virus encoded RNA were positive (Fig. 2D-F), confirming the diagnosis of ENKL.