Introduction
Signet ring cell carcinoma (SRCC) is a poorly differentiated mucin-producing adenocarcinoma with greater than 50% signet ring cells [
1]. It commonly arises from the gastrointestinal (GI) tract and rarely from extraintestinal organs [
1]. According to the World Health Organization (WHO) global cancer database [
2], gastric cancer is the fifth leading cause of cancer and the third cause of cancer death worldwide. The American Cancer Society estimates about 26,380 new cases of gastric cancer in 2022, of whom about 11,090 are expected to die [
3].
The Incidence of gastric adenocarcinoma has decreased since the inception of Helicobacter pylori (H. pylori) eradication [4,5]. However, SRCC incidence increased 10-folds between 1970 and 2000 [6]. A recent study reports that SRCC accounts for 35%-40% of cases of gastric adenocarcinoma and 1% of colorectal cancers [7]. SRCC is an aggressive carcinoma and carries a poor prognosis [
8]. The WHO classifies SRCC as a poorly cohesive carcinoma [
9], corresponding to the diffuse type of Lauren classification [
10] and the undifferentiated type of Nakamura et al. classification [
11]. SRCC comprises individual tumor cells invading the surrounding tissues with no gland formation [
1].
SRCC is generally seen in adults over 30 years [
8,
12], unlike familial gastric cancer, which is common in patients less than 30 years old [
13]. Multiple reports indicate that younger females are more affected, and more cases are reported among Asian, African, Hispanic, Pacific Islander, and Native Alaskan populations [
7,
8,
12]. The exact cause of SRCC is unknown. SRCC develops under the influence of several genetic and environmental factors [
1,
8,
12]. Genetic mutations such as E-cadherin (CDH 1) have been implicated in developing signet ring cancer [
12].
Approximately 15% of all cancer patients develop pleural effusion, with lung and breast cancer accounting for 50%-60%, followed by mesothelioma, lymphoma, and other hematologic malignancies [
14,
15].
SRCC more frequently metastasizes within the peritoneum, bone, and ovaries and less frequently to the lungs and liver than other adenocarcinomas [
1,
8,
12].
We present a rare case of a young African American female who presented with metastatic spread of signet ring cell gastric cancer (pleural and lymph nodal involvement) as the initial presentation.