A lesion was found on the left scrotal wall of a 67-year-old man 11 months ago, followed by ulceration at the surface of the lesion 6 months later. The patient was in good health before and had no history of hepatitis, diabetes, tuberculosis, or cancer. He had no history of medical, family, psychosocial, or genetic problem neither. Hard and diffuse eczematous changes and ulcerations were revealed on his left scrotum by physical examination ( Figure 1 ). Palpations of his testis and epididymis were normal, along with no swelling or palpable mass in his bilateral groins. Nothing notable was found from bloodwork and conventional chest CT. The bloodwork did however show syphilis-specific antibodies. According to the physical examination and patient history, it was initially diagnosed with a common skin disease, such as dermatitis or eczema. Since no response to a diagnostic therapy of topical ointment was found thereafter, further examinations were subsequently ordered. With relevant guidelines and regulations complied, the work was approved by the Ethical Committee of Zhejiang Hospital of Integrated Traditional Chinese and Western Medicine and informed consents were obtained from the patient.
The conventional high-frequency US examination of the lesion was performed, using the Philips iU22 Ultrasound machine (Philips Healthcare, Bothell, WA, USA) with the L12-5 linear array transducer (frequency range, 5.0-12.0 MHz). An isoechoic to hypoechoic lesion measuring 3.6 x 2.9 x 1.4 cm was found on his left-sided scrotal wall, with an infiltrative margin and cutaneous invasion (including epidermis, dermis, and hypodermis invasion). Color Doppler ultrasound showed a profuse signal of intralesional vascularity, and the resistance index was 0.76. Elastography was performed to assess the lesion stiffness, which was valued to be hard in a score of 4 according to the Itoh score system. No abnormality was found in the testis, epididymis, or bilateral groins.
A lesion with hypointensity on T1WI and heterogeneous hyperintensity on T2WI was found at his left scrotal wall by magnetic resonance (MR) (1.5 T, SIGNA Explorer, GE, Tianjin, China). However, the extent of lesion invasion was not accurately measured in such uneven location.
Subsequently, CEUS was performed with the L9-3 linear array transducer (frequency range, 3.0-9.0 MHz) and low acoustic power (mechanical index, 0.06) for further confirming the extent of the lesion before surgery. The examination was carried out by an experienced radiologist after intravenous bolus injection of 4.8 ml SonoVue  (Bracco Diagnostics Inc., Italy), flushed with 10 ml of a physiological saline solution. Rapid enhancement of the lesion was shown in CEUS, which indicated a malignant tumor. The lesion measuring 5.6 x 4.9 x 1.4 cm with hyper-enhancement in the main area and non-enhancement in the superficial area was shown in all stages, which was larger than that shown on conventional US. Then, we made marks on the skin before surgical resection.
Based on all clinical data and imaging findings, it was highly suspected as a skin malignant tumor before surgery, such as squamous cell carcinoma or adenocarcinoma of skin. Dermatosis associated with syphilis was also a possibility. Finally, a histopathological result of EMPD was confirmed after conducting biopsy on the excised lesion. It found scattered epidermal Paget cells with a pleomorphic and hyperchromatic nucleus and abundant clear cytoplasm, which were located throughout the epidermis in nest-like structures, involving full skin layers and subcutaneous soft tissue (including nerves and blood vessels). The present case showed all morphologic features of EMPD including positive immunohistochemical staining for CEA, CK7, and GCDFP-15. Moreover, the volume of the lesion on the gross specimen was 5.5 x 5.0 x 1.3 cm, which matched the result of CEUS.
The patient did not receive radiotherapy or chemotherapy after surgery and has been closely followed up to now.