A 58-year-old woman was admitted to our hospital in April 2021 for a huge, painful lump in the abdominal wall, coupled with a rapid decline in overall health. An edematous plaque in the abdominal wall inexplicably began about 13 months before admission, when she experienced a stomach ache and dizziness, simultaneously. During the interim, she experienced a gradual weight loss of 5 kg. Her plaque gradually thickened and hardened, forming many grape-like nodules on the surface.
On physical examination (Figure 1), the patient had a huge lump with bunches of grape-like appearance in the abdominal wall. When the grape-like nodules were punctured, a clear yellow fluid came out. The skin at the base of the lump appeared dark red, thickened, and hard, extending to the lower chest, upper thighs, and buttocks. No frank edema, swelling, ulcerations, or hemorrhagic lesions were found. The patient was pale and thin. The dullness of the percussion and decrease in breath sounds were noted in the lower lungs. 
The initial diagnostic workup revealed that the hemoglobin levels were 75 g/L. The other findings were as follows: reduced total protein (51.5 g/L) and albumin (29.1 g/L), lactic dehydrogenase (LDH) (247.5 U/L), carcinoembryonic antigen (CEA) (6.37 ng/mL), carbohydrate antigen (CA) 125 (248.15 U/mL), CA 199 (>400 U/mL), CA 50 (392 IU/mL), CA 242 (25.7 IU/mL), CA 724 (116 IU/mL), beta-Human chorionic gonadotropin (beta-HCG) (8.07m IU/mL), cytokeratin 19 fragment 21-1 (CYFRA 21-1) (10.6 ng/mL), pro-gastrin-releasing peptide (ProGRP) (551 pg/mL). This combination of results suggested tumors that were derived from the digestive system.
A computed tomography scan revealed extensive swelling and effusion on the walls of the chest, abdomen, and basin, in addition to interstitial pulmonary edema in both lungs, lobulated nodules in the upper apical segment of the right lung, as well as a few mucus plugs in the trachea.
Multiple vegetations on the anterior abdominal wall and bilateral thighs were observed through the positron emission tomography/computed tomography (PET/CT) scan, along with intense fluorodeoxyglucose (FDG) uptake. The other FDG-positive pathological lesions were also observed in the superior apical segment of the right lung, multiple enlarged lymph nodes in bilateral neck roots, left upper and lower clavicular fossa (Figure 2A), mediastinum, double hilum, parastinum, sternum, retroperitoneum (Figure 2B), left side of rectum and bilateral iliac vessels, nodules in the upper right posterior lobe of the liver, as well as the left upper femur and nodules of the abdominal wall (Figure 2B). Thoracentesis was done and the result of tumor biomarkers from pleural effusion was consistent with those in serum. 
A skin biopsy was performed from the grape-like nodules and dark red patches. There was lymphatic dilation, and dermal mucin deposition in both lesions, but with scattered cells having a signet-ring morphology within the deep reticular dermis and subcutis only in the dark red patch (Figure 3A). Lesion cells stained positive with cytokeratin (CK), Cam 5.2, CK 7, CK 20 and Villin (Figure 3B-D), while negative with S100, caudal type homeobox 2 (CDX 2), thyroid transcription factor -1 (TTF-1), estrogen receptor (ER), and gross cystic disease fluid protein-15 (GCDFP-15). 
The elevated tumor biomarkers in both serum and pleural effusion, together with immunophenotypic findings pointed to a metastatic SRCC of gastrointestinal origin. Therefore, esophagogastroduodenoscopy and colonoscopy with biopsy were suggested. Unfortunately, the patient developed atrial fibrillation upon the completion of esophagogastroduodenoscopy and died despite all rescue efforts. The endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) and the left clavicular fossa lymph nodes biopsy could not be completed. Under esophagogastroduodenoscopy, multiple ulcers were found in the gastric antrum and duodenal bulb, but only some inflammatory cell infiltration without tumor cells was found in the stomach tissue, histopathologically.