Diagnostic Pitfall of Gastric Signet-Ring Cells: How to Diagnose a Benign Signet-Ring Cell From a Malignant One

Sometimes non-neoplastic changes of the gastric mucosa mimic diffuse-type gastric carcinoma, specifically signet-ring cell adenocarcinoma. In fact, gastric epithelial cells undergoing signet-ring cell change have a cellular morphology that is almost identical to signet-ring cell adenocarcinoma, often leading to misdiagnosis. Accurate recognition of signet-ring cell change is essential to avoid overdiagnosis and overtreatment of signet-ring cell adenocarcinoma. Research on this topic is limited and clinicians lack formal diagnostic tools when signet-ring cells are detected in biopsy specimens. The aims of this study are 3-fold. Firstly, to increase the awareness of both clinicians and pathologists of this rare but highly significant entity. Secondly, to report 4 additional examples of signet-ring cell change and analyze them alongside signet-ring cell adenocarcinoma to compare their morphological and phenotypic features and their evolution over time. Finally, to highlight the potential utility of endoscopic resection to confirm the diagnosis. Cells in signet-ring cell change strongly express E-cadherin, show a wild-type p53 expression, and have a low Ki67 index. In contrast, cells in signet-ring cell adenocarcinoma strongly express p53, have high proliferation rates, and show either no or weak E-cadherin staining. Genetic analysis may be useful in identifying patients at risk of hereditary early diffuse gastric adenocarcinoma, which can mimic signet-ring cell change.

Unusual Metastasis of Gastric Signet Ring Cell Carcinoma to the Breast: A Case Report of a Young Moroccan Patient

Although gastric cancer is known to be an aggressive tumor that can spread throughout the body, breast metastases are uncommon. This entity is rarely reported in the literature, with an estimated incidence of 0.5 to 1.3%. We report a case of a rare association between a gastric subtype of signet ring cell carcinoma and metastasis to the breast. This uncommon situation is only documented through case reports. Most breast metastases have been detected after diagnosis of primary gastric cancer, during the first year. Several risk factors have been suggested to explain the aggressive behavior of these tumors, which correlates with very poor prognosis and short survival. We report the case of a 22-year-old female patient presenting with widespread metastatic gastric signet ring cell carcinoma with an unusual secondary site in the breast. The diagnosis was confirmed by immunohistochemistry (IHC) and radiology, and the patient was treated with palliative chemotherapy in accordance with the decision of the multidisciplinary tumor board.

Colloid Carcinoma Arising in an Intestinal-Type Intraductal Papillary Mucinous Neoplasm with High-Grade Dysplasia Appearing as Signet-Ring Cells of the Pancreas by Serial Pancreatic Juice Aspiration Cytology: A Case Report

We report a case of colloid carcinoma (CC) arising from an intestinal-type intraductal papillary mucinous neoplasm with high-grade dysplasia (IPMNHGD) of the pancreas, diagnosed with serial pancreatic juice aspiration cytological examination (SPACE). A rapidly growing intraductal papillary mucinous neoplasm (IPMN) in a 71-year-old Japanese man accelerated his hospitalization in our institute. Clinically, a large, ruptured pancreatic cyst was suspected. Cytologically, several mucin-positive signet-ring cells were scattered in the inflammatory, necrotic, or mucinous background. Signet-ring cells in cell block specimens were immunoreactive for MUC2, MUC5AC, maspin, S100P, and claudin-18. The final cytologic diagnosis was CC arising in an intestinal-type IPMNHGD with intraperitoneal penetration. The patient died two months after an explorative laparotomy. The cytologic diagnosis was achieved through SPACE, and the presence of signet-ring cells was characteristic. Anti-claudin-18.2-specific monoclonal antibody therapy will likely be used to treat patients with IPMNHGD in the future. This case highlights the diagnostic utility of SPACE, with particular emphasis on the characteristic presence of signet-ring cells. Furthermore, it anticipates the potential use of anti-claudin-18.2- specific monoclonal antibody therapy in the management of IPMNHGD patients.

Primary signet‑ring cell melanoma of the anorectum: A case report

Malignant melanoma is one of the most common malignant tumors. Although its incidence rate is generally low among the Chinese population, it has grown rapidly in recent years. The incidence of primary malignant melanoma in the digestive tract is very low. The incidence in the esophagus and rectum are more common, while reports in the colon are only reported in <10 cases. Primary signet ring cell carcinoma of the rectum is also a rare and unique tumor. This paper reports a case of rectal malignant melanoma with signet ring cell carcinoma.

Signet-Ring Cell Squamous Cell Carcinoma: A Biphenotypic Neoplasm of the Gastro-Esophageal Junction with Uncertain Biological Potential: Case Report and Literature Review

The signet-ring cell variant of squamous cell carcinoma (SCC) is an extremely rare histological subtype, with only 24 cases (including the present case) reported in the Medline database: 15 affecting the external surface of the body, 3 in the lung, 2 affecting the uterine cervix, 1 involving the gingiva, another one affecting the esophagus and the present case that is the first reported at the gastro-esophageal junction (GEJ). In one case, the location of the lesion was not mentioned. A 59-year-old male patient underwent segmental eso-gastrectomy for carcinoma of the GEJ. The microscopic examination showed a pT3N1-staged SCC composed of solid nests admixed in over 30% of the tumor, with cells having eccentrically located nuclei and clear vacuolated cytoplasm. The signet-ring cells did not show mucinous secretion and were positive for keratin 5/6 and vimentin, with nuclear expression of β-catenin and Sox2 and focal membrane positivity for E-cadherin. Based on these features, the case was considered a signet-ring SCC with epithelial-mesenchymal transition. Thirty-one months after surgery, the patient was disease-free, with no local recurrence and no known distant metastases. In SCC, a signet-ring cell component might be an indicator of the dedifferentiation of tumor cells towards a mesenchymal molecular subtype.

The challenging presentation of gastric cancer during pregnancy with krukenberg tumor: a case report

The incidence of ovarian tumors in pregnancy is around 0.05%. Primary ovarian cancer and metastatic malignancy are rare in pregnancy, and women often delayed in diagnosis.

Importance

This is the first case ever reported on gastric cancer diagnosed during pregnancy presenting with a Krukenberg tumor and mimic ovarian tumor torsion, cholecystitis. By reporting this case, we could sensitize physicians to be more vigilance of abnormal abdominal pain in pregnant women.

Case presentation

A 30-year-old female came to our hospital at the 30th week of gestational age due to preterm uterine contraction and worsening abdominal pain. A cesarean section was performed due to preterm uterine contraction and intolerable abdominal pain suspected to be ovarian torsion. Microscopic examination of the ovarian specimen showed signet-ring cells. The patient was diagnosed with gastric adenocarcinoma at stage IV after complete surveillance. Postpartum chemotherapy consisted of oxaliplatin and high-dose 5-fluorouracil. The patient died 4 months after delivery.

Clinical discussion

Malignancies during pregnancy should be kept in mind while encountering atypical clinical presentations. Krukenburg tumor is rare in pregnancy and gastric cancer is the most common cause. Early diagnosis of the gastric cancer in the operable stage is the key to a better prognosis.

Conclusion

Diagnostic examinations for gastric cancer in pregnancy could be performed after first trimester. Treatment should be introduced after balancing maternal-fetal risks. Early diagnosis and intervention are crucial to decrease the high mortality rate of gastric cancer in pregnancy.

Pleural metastasis from pulmonary primary signet-ring squamous cell carcinoma. Case report and literature review

Signet-ring cells are morphologically defined by the presence of a large intracytoplasmic vacuole that compresses and displaces the nucleus to the periphery. In most cases, these cells are associated with adenocarcinomas of various locations, and with non-epithelial neoplasms. To date, less than 20 cases of squamous cell carcinoma with signet-ring morphology have been described, mainly located on the skin. We present the case of a 73-year-old male with pleural effusion and a left lower lobe mass. The cytological study of the pleural effusion allowed the diagnosis of metastasis of squamous cell carcinoma, signet-ring cell variant. The treatment of lung cancer in advanced stages requires a precise diagnosis that allows the best therapy to be offered to the patient, depending on the clinical stage and the positivity of the biomarkers, among others. Our patient died 18 months after the initial diagnosis.

Cutaneous Amelanotic Signet-Ring Melanoma in a Siberian Tiger (Panthera tigris altaica)

A 15-year-old male white Siberian tiger (Panthera tigris altaica) was evaluated for an elevated, ulcerated, cutaneous mass on the right flank. The mass was removed by excisional biopsy and submitted for histopathology. Based on distinct histological features of intracytoplasmic globular material and positive immunohistochemical staining for Melan-A and vimentin, an amelanotic signet-ring melanoma was diagnosed. While in domestic cats this neoplasm is associated with malignancy and a short survival time, the tiger had no local recurrence or related clinical disease approximately 4 years post surgery. Cutaneous melanocytic tumours are rare in big cats, and the findings in this case suggest that amelanotic signet-ring melanoma is not as malignant as its counterpart in domestic cats.

Acute Appendicitis with Neuronal Hyperplasia and Swelling: A Novel Histologic Mimic of Appendiceal Goblet Cell Adenocarcinoma and Signet-Ring Cell Adenocarcinoma

Goblet cell adenocarcinoma and signet-ring cell adenocarcinoma are well-known diagnostic pitfalls of routine appendectomy specimens. Here we present a case of acute appendicitis with prominent neuronal (ganglion cell) hyperplasia and swelling which histologically mimics goblet cell adenocarcinoma and signet-ring cell adenocarcinoma. Attention to the cytologic features of the lesional cells (absence of atypia, mitotic activity) and their close association with nerves and classic ganglion cells, along with the use of a limited panel of immunostains, ensures proper classification of this rare but striking benign process.

Livedoid cutaneous metastasis of signet-ring cell gastric carcinoma

Cutaneous metastasis of gastric cancer is extremely rare. Nodular forms are more common and inflammatory forms are exceptionally encountered. Herein, we report a case of inflammatory cutaneous metastasis of signet-ring cell gastric cancer (poorly cohesive gastric carcinoma with signet-ring cell component) masquerading as livedo reticularis. To our knowledge, such a clinical presentation of cutaneous metastasis has not been reported for gastric cancer. It is imperative to preserve a high index of clinical suspicion for diagnosing cutaneous metastases. Our case highlights the importance of obtaining a skin biopsy in patients with a known history of internal malignancy. Bizarre, newly erupting, evolving, persistent, or treatment-refractory dermatologic lesions (such as nodules, ulcers, erythematous, reticular, or livedoid patches) might be clues for an underlying internal malignancy and require prompt histopathological sampling. Personal medical history, histopathological examination, and immunohistochemical profiling are equally important in distinguishing primary cutaneous carcinomas from secondary metastatic deposits. Early recognition of a cutaneous metastasis might enable appropriate staging and timely intervention, thereby prolonging survival.

The Clinicopathological Characteristics And Genetic Alterations of Signet-ring Cell Carcinoma in Gastric Cancer

Signet-ring cell carcinoma (SRC) in advanced gastric cancer (GC) is often associated with more invasiveness and a worse prognosis than other cell types. The genetic alterations associated with gastric carcinogenesis in SRC are still unclear. In this study, 441 GC patients receiving curative surgery for GC between 2005 and 2013 were enrolled. The clinicopathological characteristics and genetic alterations of GC patients with and without SRC were compared. Among the 441 GC patients, 181 had SRC. For early GC, patients with SRC had more tumors located in the middle and lower stomach, more infiltrating tumors and better overall survival (OS) rates than those without SRC. For advanced GC, patients with SRC had more scirrhous type tumors, more PIK3CA amplifications, fewer microsatellite instability-high (MSI-H) tumors, more peritoneal recurrences and worse 5-year OS rates than those without SRC. For advanced GC with SRC, patients with peritoneal recurrence tended to have PD-L1 expression. For advanced GC without SRC, patients with liver metastasis tended to have PD-L1 expression, PI3K/AKT pathway mutations, TP53 mutations and MSI-H tumors. For advanced GC, PD-L1 expression was associated with peritoneal recurrence in SRC tumors, while non-SRC tumors with liver metastasis were likely to have PI3K/AKT pathway mutations, TP53 mutations and PD-L1 expression; immunotherapy and targeted therapy may be beneficial for these patients.

Unusual case of primary cutaneous signet-ring cell (histocytoid) carcinoma

Signet-ring cell (histocytoid) carcinoma is a rare and aggressive skin neoplasm that most commonly affects elderly men. It typically originates from the upper or lower eyelid, with bilateral involvement only in rare cases, and results in a diffuse and infiltrative appearance clinically, radiologically, and histologically (the "monocle" sign). It is essential to carry out a full investigation to rule out metastasis from an internal origin.

A case of primary signet-ring cell carcinoma of the cervix containing full genome of human papillomavirus 16

We herein present a case of primary signet-ring cell carcinoma of the cervix. Pelvic magnetic resonance imaging revealed a 38-mm cervical tumor, and computed tomography revealed no findings suggestive of distal metastasis or other tumor origins. Gastrointestinal endoscopy showed no abnormal findings. Histopathology revealed signet-ring cell-type mucinous adenocarcinoma. By immunohistochemistry, tumor cells were negative for the mammary neoplasm marker, gross cystic disease fluid protein 15 and gastrointestinal neoplasm markers, MUC2, MUC6, and CDX2, but positive for p16. These findings suggested human papillomavirus (HPV)-related adenocarcinoma of the cervix. HPV genotyping assays with exfoliated cervical cells and formalin-fixed paraffin-embedded tissues demonstrated HPV16 positivity, suggesting that the primary origin of the tumor was the cervix. The full HPV16 genome was amplified by polymerase chain reaction from exfoliated cervical cells, and the full-genome sequence was determined by next-generation sequencing. This is the first report of primary signet-ring cell carcinoma of the cervix containing the full HPV16 genome.

Signet-ring cells in the bone marrow as an indication of cryptic metastasis of breast carcinoma: A case report

RATIONALE

Signet-ring cell is a rare morphological finding in bone marrow, which usually indicates metastatic carcinoma from either the gastrointestinal tract or a primary hematolymphoid neoplasm. Here, we present a very unusual case of lobular breast carcinoma with metastasis to the bone marrow.

PATIENT CONCERNS

A 67-year-old female with estrogen receptor (ER)-positive lobular breast carcinoma was staged as T3N3M0, and treated with modified radical mastectomy followed by chemotherapy and radiotherapy. One year after treatment, she was noted to have moderate thrombocytopenia on complete blood count with the remainder of the parameters within normal limits. Radiographic examination revealed no evidence of recurrent disease.

DIAGNOSIS

Bone marrow biopsy was performed to exclude therapy-related myelodysplastic syndrome (MDS), which demonstrated hypercellularity with "hyperplastic" hematopoiesis. Upon closer inspection, a few signet-ring cells were identified which morphologically resembled histiocytes. These formed an interstitial infiltrate among the predominantly hematopoietic elements, and could have been easily overlooked. Immunohistochemistry demonstrated that these signet-ring cells were positive for pancytokeratin as well as ER which confirmed metastatic lobular breast carcinoma. On retrospective review of the aspirate smear, rare signet-ring cells were identified.

INTERVENTIONS

The patient was treated with additional chemotherapy.

OUTCOMES

The patient eventually succumbed to overt dissemination after 14 months.

LESSONS

Due to the relative discohesiveness of lobular breast carcinoma, the cells frequently assume single-cell infiltration in bone marrow. This attribute, along with small cell size, bland cytologic features and paucity of tissue response, contributes to its escaping from identification on hematoxylin-eosin (H&E) sections. In this case, the signet-ring cells were hidden in apparently hyperplastic hematopoiesis. Careful inspection raised the possibility of occult metastasis which was readily detected and confirmed with immunohistochemistry.

Metastatic tumor of male genital system from gastric cancer: a case report and review of literature

Spermatic cord (SC) tumor metastatic from gastric cancer (GC) is rare. Here we report a case of left SC metastasis and meanwhile perform a literature review to characterize this rare disease. A 72-year-old male presented with a palpable painful mass in the left groin after one year and a half of remnant GC resection. SC metastasis of signet-ring cell adenocarcinoma was confirmed by trans-inguinal biopsy, and palliative chemoradiotherapy was initiated. The disease remained stable within follow-up 10 months. A total of 27 GC patients with male sex cord metastasis were reviewed according to a literature search from January 1955 to March 2016. In such a cohort, the mean age was 58.3 (range, 23-72) years. The average time interval between primary GC and genital metastasis was 43.2 (range, 2-120) months in 16 (59.3%) metachronous cases, while nine (33.3%) synchronous cases reported. The average size of genital tumor was 3.8 (range, 2.1-9.0) cm in diameter. The major pathological characteristics were signet-ring cell (40.0%, 8/20) and poor differentiation (85.0%, 17/20), with right-side sex cord most commonly involved (48.1%). The incidence of genial metastasis was 74.1% in SC, with 40.7% for epididymis, 33.3% for testis, 14.8% for tunica vaginalis and 3.7% for scrotum. The one-year overall survival rate was 38.7%, with a median survival time of 12 months. Advanced GC metastatic to male sex cord is rare, with poor prognosis. For patients with GC history and groin discomfort or mass, metastatic adenocarcinoma should be suspected, followed by proper diagnosis and treatment.

Intraoperative peritoneal lavage cytology offers prognostic significance for gastric cancer patients with curative resection

Outcomes of patients with gastric cancer who exhibit positive peritoneal lavage cytology findings (CY⁺ ) vary by diagnostic methods because of quantitative and qualitative cancer cell diversity. This study sought to establish practical diagnostic criteria for performing curative resections, based on peritoneal lavage cytology findings in gastric cancer patients. We enrolled 1028 patients with gastric cancer who underwent R0/1 (n = 911) or R2 (n = 117) resections and analyzed relationships between cancer cell findings in peritoneal lavage fluid and clinicopathological factors in the R0/1 group. We found 68 patients with CY⁺ status. Receiver operating characteristic analyses and multivariate analyses showed that the presence of ≥1 signet ring cell, ≥5 cell clusters or ≥50 isolated cancer cells in peritoneal lavage fluid predicted poor prognoses in the 68 CY⁺ patients. High-risk CY⁺ group patients with at least one of the above predictors had the highest hazard ratio (HR = 3.28, P < 0.001). The remaining (low-risk) patients had a survival curve similar to that of patients with a normal cytology. The high-risk CY⁺ patients who underwent R1 resection had poor prognoses despite no macroscopic peritoneal metastasis (2% 5-year survival)-equivalent to that of patients who underwent R2 resection. The CY⁺ criteria defined in this study could help identify candidates for curative resection as an initial therapy for gastric cancer.