Clinical History
A 45-year-old male patient was initially diagnosed with gastric cardia tumour with supraclavicular nodal metastasis. Baseline positron emission tomography (PET) and serum tumour markers normalised after neoadjuvant chemotherapy.
Afterwards, he underwent complete gastrectomy with Roux-en-Y reconstruction plus lymphadenectomy. Surgical pathology reported residual pT1bN0 adenocarcinoma with negative peritoneal lavage, omentum and lymph nodes.
Imaging Findings
Preoperatively, the residual tumour of the gastric cardia after neoadjuvant chemotherapy was depicted by multidetector CT with gastric distension by oral water and pharmacological hypotonisation (Fig. 1a, b), without extramural invasion, nodal or distant metastases.
Days after surgery, upper gastrointestinal series with water-soluble contrast medium documented complete gastrectomy with patent Roux-en-Y anastomosis (Fig. 1c).
Before adjuvant chemotherapy initiation, CT (Fig. 2) showed normal post-surgical status without any signs of neoplastic recurrence.
Currently, after three cycles of chemotherapy, repeated CT (Fig. 3) showed appearance of left-sided pleural effusion and atelectatic basal lung consolidation. Innumerable small-sized poorly enhancing solid masses consistent with metastatic deposits occupied most of the ipsilateral perirenal space, surrounding the kidney with delayed nephrographic appearance from probable vascular compression.
Despite second-line treatment clinical deterioration occurred. Further CT (Fig. 4) showed increased ascites, mesenterial adenopathies, appearance of small-sized liver metastases and decreased perirenal metastases. The patient ultimately passed away with the development of brain metastases.
Discussion
Contrarily to the more common stomach tumours, adenocarcinoma of the gastric cardia (AGC) is increasingly encountered and typically associated with a dismal prognosis due to advanced disease at presentation and aggressive behaviour. The 5-year survival rates are 38% and 8% for stages I+II and III+IV respectively. Compared to distal cancers, AGC have mean larger size, and higher incidence of serosal invasion, lymphatic and blood vessel invasion, nodal and peritoneal metastases. Prognostic factors include surgical radicality, histological type and differentiation, and TNM stage [1, 2].
Following surgical resection, AGC recurs in approximately 70% of patients within 2 years and mostly spreads intra-abdominally but with protean manifestations. Neoplastic recurrence may be locoregional 36% (including those in the distal mediastinum, the resection margins and the organ used for reconstruction), nodal (70%), peritoneal, distant (43-64%), or combined. Haematogenous metastases involve the liver (31%), peritoneum (17%) and lung (17%) in descending order of frequency [1, 2].
As this case exemplifies, occasionally tumour recurrence may selectively involve the perirenal space (PS), which is one of the main retroperitoneal compartments and contains the adrenal gland, kidney, proximal ureter surrounded by fat, bridging connective tissue and vessels. The PS may be reached through local spread from other compartments, particularly in lung cancers with mediastinal or pleural involvement. Alternatively, PS metastases may develop from lymphatic extension or by haematogenous dissemination due to its rich vascular supply. Isolated PS metastases are uncommon. Most often encountered in the setting of disseminated neoplastic disease, PS metastases have been reported in patients with melanoma, prostate, breast and gastrointestinal tumours [3-6].
In conclusion, when interpreting oncologic CT studies radiologists should remember that the PS may sometimes harbour distant metastases, which appear as multiple discrete soft-tissue masses with variable contrast enhancement depending on the histotype of the primary tumour [3-6].
Differential Diagnosis List
Perirenal metastases from resected adenocarcinoma of the gastric cardia.
Lymphoma
Leukaemia/Plasma cell neoplasms
Castleman’s disease
Extramedullary haematopoiesis
Idiopathic retroperitoneal fibrosis
Erdheim-Chester disease
Final Diagnosis
Perirenal metastases from resected adenocarcinoma of the gastric cardia.
