Two months prior to presentation, the patient, a 41-year-old woman, was accidentally bitten by a "wild dog" on the skin at the back of the middle and lower parts of the right leg while walking. After the incident, the patient experienced a localized pain and discomfort associated with minimal bleeding. Later, she went to the District People's Hospital for wound treatment. She was administered with the tetanus antitoxin and rabies vaccine. Subsequently, the patient self-managed the wound without much success with the healing process. Twenty days before admission, no obvious cause of skin redness and swelling were observed on the inner skin of the proximal right thigh of the patient. Initially, the patient did not pay much attention to it. The area of redness and swelling increased to 14 cm x 5 cm, with slight pain and discomfort. Concurrently, the wound site began to ooze a secretion. Therefore, she revisited the District People's Hospital and was administered with topical drugs for disinfection and antibacterial treatment (the specific drug name is unknown). After symptomatic treatment, the volume of the secretion from the wound surface decreased slightly. However, the signs of redness and swelling in the right thigh increased. Subsequently, the patient was treated at our outpatient department. After treatment, the secretion from the wound site ceased. The swelling of her right thigh was slightly reduced, but the skin around the wound site was broken and exudative. For further management, the patient was admitted for treatment of a skin abscess. Since the onset of the disease, no symptoms and signs of appetite loss, sleep disturbance, stool and urine-associated changes, and weight loss were reported.
Further laboratory investigations after admission showed that the infection indicators, such as white blood cell count, neutrophils C-reactive protein, and procalcitonin, were normal. Liver function, renal function, electrolyte balance, routine blood parameters, chest radiograph, and electrocardiogram were normal. As shown in Fig. 1A, a physical examination revealed the presence of an irregular skin redness and swelling of size of about 3.0 cm x 2.5 cm at the posterior aspect of the midsection of the right leg. The surface could be covered by an irregular scab shell of about 1.00 cm x 0.8 cm. The adhesion was not tight. After the scab shell was opened, a small amount of necrotic tissue was observed under the scab. A minimal amount of purulent secretion could be observed around the extrusion. A red and swollen skin of size, 14 cm x 6.0 cm, was observed on the inner side of the right thigh. The texture of the local skin was relatively tough. Two oval skin ulcer wounds of about 2.0 cm x 1.0 cm were present (Fig. 1B). The necrotic skin was attached to the wound surface with relative tightness. A light microwave motion could be observed whenever the inner ulcer was squeezed. After the necrotic skin was removed from the wound surface, necrotic tissues with associated minimal purulent secretions in the tissue gaps were observed. From experience, we used Laxef sodium for its anti-infection effect. We further incised and drained the abscess on the right thigh. Culture of the purulent secretion obtained from the wound site revealed the presence of the Staphylococcus squirrel subspecies. The wound healed well after symptomatic treatment by anti-infection and dressing change. The patient was discharged 7 days after the procedure.
Three days after discharge, the patient found a mass of about 4 cm x 4 cm in size on the medial side of the right thigh (Fig. 2). The mass was associated with tenderness, no wave motion and skin temperature rise. Therefore, she revisited the hospital. Upon admission, various laboratory investigations showed no abnormalities in liver function, renal function, electrolyte balance, and routine blood parameters. An ultrasound examination showed a fluid accumulation under the right thigh root incision. The ranges of two dark areas under the right thigh root incision were 3.0 cm x 1.9 cm x 1.0 cm and 4.0 cm x 3.5 cm x 1.6 cm (Fig. 3). We performed a local puncture and extracted 25 ml of clear yellowish liquid (Fig. 4). No positive findings were obtained from acid-fast staining, fungal culture, and bacterial culture. Thereafter, the mass on the proximal end of the right thigh was resected again. During the operation, the skin, fat, and superficial fascia layers were cut to locate the two liquid dark areas shown by ultrasonography. The liquids in both areas were yellow and clear, and they communicated with each other through the sinus. Two swollen lymph nodes were found above the liquid dark area. After blunt separation, two dark and necrotic lymph nodes with sizes of 3.0 cm x 2.0 cm and 0.5 cm x 0.5 cm were found (Fig. 5). We completely excised the lymph nodes, ligated lymph vessels, and reduced tension sutured after hemostasis. Postoperative pathological examination showed that the right inguinal lymph node had undergone a caseous necrotizing granulomatous inflammation. A test for nucleic acids of Mycobacterium tuberculosis was negative (Fig. 6). After the operation, the patient were treated by anti-infection, pressure bandaging, and dressing change. She was discharged afterwards.