Pelvic masses frequently originate from the pelvic cavity and are often associated with uterine, ovarian, or intestinal disorders. This report describes the case of a patient with a pelvic mass diagnosed as a retroperitoneal dermoid cyst at our hospital. We analyzed this case and conducted a literature review, to mitigate the risk of misdiagnosis and enhance the treatment of retroperitoneal masses.

SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily A member 4 (SMARCA4)-deficient tumors are rare and highly aggressive tumors characterized by a loss of SMARCA4 expression, and SMARCA4-deficient tumors in the adnexal area of the uterus are particularly rare. The present study describes the case of a 64-year-old woman who was admitted to Weifang People\'s Hospital (Weifang, China) with abdominal distension, and was observed to have a mass with ascites in the adnexal area of the uterus. Based on clinical, imaging and pathological findings, the patient was diagnosed with a SMARCA4-deficient adnexal tumor with ascites. Biopsy of the left and right adnexal lesions was performed, and the patient was administered chemotherapy. After one cycle of bevacizumab, sindilizumab and carboplatin, no further treatment was administered. After biopsy and chemotherapy, the abdominal distension was alleviated and the general condition of the patient was satisfactory. The patient was followed up and died 3 months after treatment. Notably, it is important to avoid misdiagnosing this tumor as other types of adnexal uterine tumors, and morphological and immunohistochemical features may be useful for diagnosing primary SMARCA4-deficient tumors in the adnexal area of the uterus.

Chronic active Epstein-Barr virus (EBV) infection-associated enteritis (CAEAE) in nonimmunodeficient individuals is rare. To report a case of CAEAE, relevant articles were searched through databases. The clinical manifestations, endoscopic findings, strategies of treatment, prognoses, and follow-up results of CAEAE patients were analyzed. Including this report, seven citations in the literature provide descriptions of 27 cases of CAEAE. There were 21 males and six females, with a mean age of 40 years. The main clinical manifestations were fever (25/27), abdominal pain (14/27), diarrhea (16/27), hematochezia or bloody stools (13/27), and decreased hemoglobin and red blood cell counts in routine blood tests (14/27). Elevations in inflammatory markers, white blood cell (WBC) counts, and C-reactive protein (CRP) were common. Coagulation was often abnormal. Histopathology confirmed EBV-encoded small nuclear RNA (EBER) in the affected tissue via in situ hybridization. The average serum EBV DNA load was 6.3 × 10^5 copies/mL. All patients had varying degrees of intestinal ulcers endoscopically, and the ulcers and pathology were uncharacterized and misdiagnosed mostly as inflammatory bowel disease (IBD). The course of the disease was progressive and later complicated by intestinal bleeding, intestinal perforation, septic shock, and a high rate of emergency surgery. However, the conditions of the patients often did not improve after surgery, and some patients soon died due to reperforation or massive hematochezia. Hormone and antiviral treatment had no obvious effect. There was a significant difference in surgical and nonsurgical survival (p < 0.05). The proportion of patients who died within 6 months was as high as 63.6% (7/11). CAEAE belongs to a group of rare, difficult conditions, has an insidious clinical course, has a high case fatality rate, and may later develop into EBV-positive lymphoproliferative disorder (EBV-LPD), which in turn leads to carcinogenesis. Clinicians should raise awareness that in patients with multiple ulcers in the intestine of unknown etiology, attention should be paid to EBV serology, and histology to make the diagnosis as early as possible.

BACKGROUND: Acral amelanotic melanomas (AAMs), a rare subset of melanomas located on acral sites such as the palms, soles, and subungual areas, are diagnostically challenging due to their lack of typical pigmentation and often benign clinical appearance. Misdiagnosis is common, leading to delays in treatment and potentially worse outcomes. This systematic review aims to synthesise evidence on cases of AAM initially misdiagnosed as other conditions, to better understand their clinical and epidemiological characteristics, diagnostic pitfalls, and management strategies.
METHODS: A comprehensive search of the MEDLINE/PubMed, EMBASE, and SCOPUS databases was conducted up to March 2024. Case reports and small case series of AAMs initially misdiagnosed as other conditions were included. Data on patient demographics, clinical presentation, and diagnostic methods were collected and analyzed.
RESULTS: Of the 152 records identified, 26 cases from 23 articles met the inclusion criteria. A demographic analysis revealed that the gender distribution appears to be perfectly balanced, with an age range of 38 to 91 years. Misdiagnoses included non-healing ulcers or traumatic lesions (37.5%), benign proliferative lesions (29.2%) and infectious lesions (20.8%). The foot was the most affected site (53.8%). Notably, a histological evaluation was performed in 50% of cases involving the upper extremities, in contrast to only 7.1% of cases involving the foot and 0% of cases of the heel. This discrepancy suggests a reluctance to perform biopsies in the lower extremities, which may contribute to a higher misdiagnosis rate in these areas.
CONCLUSIONS: The underutilization of biopsy in the diagnosis of lower extremity lesions contributes significantly to the misdiagnosis and delay in treatment of AAMs. Especially when the clinical assessment and dermoscopy are inconclusive, biopsies of suspicious lesions are essential. Immunohistochemistry and markers such as PRAME are critical in differentiating melanoma from other malignancies such as clear cell sarcoma. This review highlights the need for increased vigilance and a proactive diagnostic approach to increase early detection rates and improve prognostic outcomes.

Pseudomyxoma peritonei (PMP) is a rare intra-abdominal malignancy characterized by diffuse dissemination of mucinous tumor cells, leading to mucinous ascites. Accurate diagnosis is crucial for appropriate management. This report presents a case of a 55-year-old Lebanese male farmer initially misdiagnosed with liver cirrhosis who presented with progressive abdominal distension refractory to diuretics and dietary modifications. Paracentesis revealed a mucinous exudate, with subsequent clinical and histopathological examination confirming PMP. The patient was referred for further evaluation at a specialized center equipped for cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). This case highlights the diagnostic challenges of PMP due to its non-specific presentation, emphasizing the importance of prompt and accurate diagnosis to facilitate optimal therapeutic intervention.

BACKGROUND: Ghost cell odontogenic carcinoma (GCOC) is a rare malignancy characterized by the presence of ghost cells, preferably in the maxilla. Only slightly more than 50 case reports of GCOC have been documented to date. Due to the rarity of this tumor and its nonspecific clinical criteria, there is a heightened risk of misdiagnosis in clinical examination, imaging findings, and pathology interpretation.
METHODS: A 50-year-old male patient presented to the hospital due to experiencing pain in his lower front teeth while eating for the past 2 months. Upon examination, a red, hard, painless mass was found in his left lower jaw, measuring approximately 4.0 cm × 3.5 cm. Based on the malignant histological morphology of the tumor and the abundant red-stained keratinized material, the preoperative frozen section pathology misdiagnosed it as squamous cell carcinoma (SCC). The surgical resection specimen pathology via paraffin section revealed that the tumor was characterized by round-like epithelial islands within the fibrous interstitium, accompanied by a large number of ghost cells and some dysplastic dentin with infiltrative growth. The malignant components displayed marked heterogeneity and mitotic activity. Additionally, a calcified cystic tumor component of odontogenic origin was observed. Hemorrhage, necrosis, and calcifications were present, with a foreign body reaction around ghost cells. Immunoreactivity for β-catenin showed strong nuclear positivity in tumor cells, while immunostaining was completely negative for p53. The Ki67 proliferation index was approximately 30-40%. The tumor cells exhibited diffuse CK5/6, p63, and p40 immunoreactivity, with varying immunopositivity for EMA. Furthermore, no BRAFV600E mutation was identified by ARMS-PCR. The final pathology confirmed that the tumor was a mandible GCOC.
CONCLUSIONS: We have reported and summarized for the first time the specific manifestations of GCOC in frozen section pathology and possible pitfalls in misdiagnosis. We also reviewed and summarized the etiology, pathological features, molecular characteristics, differential diagnosis, imaging features, and current main treatment options for GCOC. Due to its rarity, the diagnosis and treatment of this disease still face certain challenges. A correct understanding of the pathological morphology of GCOC, distinguishing the ghost cells and the secondary stromal reaction around them, is crucial for reducing misdiagnosis rates.

BACKGROUND: Sarcoidosis is a chronic inflammatory granulomatous disease of unknown cause. Delays in diagnosis can result in disease progression and poorer outcomes for patients. Our aim was to review the current literature to determine the overall diagnostic delay of sarcoidosis, factors associated with diagnostic delay, and the experiences of people with sarcoidosis of diagnostic delay.
METHODS: Three databases (PubMed/Medline, Scopus, and ProQuest) and grey literature sources were searched. Random effects inverse variance meta-analysis was used to pool mean diagnostic delay in all types of sarcoidosis subgroup analysis. Diagnostic delay was defined as the time from reported onset of symptoms to diagnosis of sarcoidosis.
RESULTS: We identified 374 titles, of which 29 studies were included in the review, with an overall sample of 1531 (694 females, 837 males). The overall mean diagnostic delay in all types of sarcoidosis was 7.93 months (95% CI 1.21 to 14.64 months). Meta-aggregation of factors related to diagnostic delay in the included studies identified three categories: (1) the complex and rare features of sarcoidosis, (2) healthcare factors and (3) patient-centred factors. Meta-aggregation of outcomes reported in case studies revealed that the three most frequent outcomes associated with diagnostic delay were: (1) incorrect diagnosis, (2) incorrect treatment and (3) development of complications/disease progression. There was no significant difference in diagnostic delay between countries with gatekeeper health systems (where consumers are referred from a primary care clinician to specialist care) and countries with non-gatekeeper systems. No qualitative studies examining people\'s experiences of diagnostic delay were identified.
CONCLUSIONS: The mean diagnostic delay for sarcoidosis is almost 8 months, which has objective consequences for patient management. On the other hand, there is a paucity of evidence about the experience of diagnostic delay in sarcoidosis and factors related to this. Gaining an understanding of people\'s experiences while seeking a diagnosis of sarcoidosis is vital to gain insight into factors that may contribute to delays, and subsequently inform strategies, tools and training activities aimed at increasing clinician and public awareness about this rare condition.
BACKGROUND: PROSPERO Registration number: CRD42022307236.

Multiple myeloma (MM) and bone metastases are both common malignant tumors of the skeleton that share similar clinical manifestations and radiological features. The development of MM following rectal cancer surgery is relatively rare in clinical practice and is easily misdiagnosed as bone metastasis. The present study reported on a patient with MM and postoperative rectal cancer. A 65-year-old man had been diagnosed with low rectal cancer (poorly differentiated, T3N1M0) 10 years prior and underwent curative treatment at that time. During the 6-year follow-up period, no recurrence or metastasis of rectal cancer was detected. The patient was evaluated for bone pain 4 years ago and underwent multiple imaging examinations, including computed tomography (CT), magnetic resonance imaging, emission CT and positron emission tomography/CT at several well-known hospitals in China. All of these hospitals diagnosed the patient with bone metastasis from rectal cancer, in view of the earlier history. The patient\'s condition did not show any significant improvement despite treatment for bone metastasis. Subsequently, 3 years ago, the patient underwent surgical treatment at our hospital (Affiliated Hospital of Zunyi Medical University, Zunyi, China) for a hernia near the colostomy site combined with incomplete intestinal obstruction. Post-operatively, the patient developed a hematoma in the surgical area, along with stubborn anemia and abnormal coagulation function. No improvement was observed with hemostasis and multiple blood transfusions. The bone marrow smear was consistent with MM, with a significant elevation in serum IgA and β2 microglobulin. The patient was ultimately diagnosed with MM (IgA-λ type), stage III, according to the Durie-Salmon staging system. The patient\'s condition improved with treatment for MM.

Laryngeal paraganglioma (LP) is an exceptionally rare neuroendocrine tumor, underscoring importance of accurate identification to preclude misdiagnoses. In this review, we presented two typical misdiagnosed LPs, and offered reviews of LP cases reported over the preceding decade and all documented misdiagnosed LP cases. Furthermore, we systematically investigated the underlying causes of misdiagnosis and elucidated key points for effective differentiation. A retrospective analysis of 28 LP cases revealed a predominant occurrence in middle-aged women, with an average history of 25.1 months. Through an analysis of all misdiagnosed cases (n = 37), supraglottic LPs were frequently misidentified as laryngeal carcinomas and vascular tumors, while subglottic LPs were often misdiagnosed as thyroid cancers. And the occurrence of misdiagnosis resulted in delayed and inappropriate treatments, contributing to the deterioration of LP patients (14 cases, 37.8%). In conclusion, this review endeavored to heighten awareness of LPs, with the ultimate goal of advancing diagnostic precision and enhancing patient outcomes.

UNASSIGNED: Solid pseudopapillary neoplasms (SPNs) of the pancreas are uncommon, low-malignancy neoplasms. Moreover, the occurrence of extrapancreatic SPNs is rarely encountered.
UNASSIGNED: A 45-year-old female presented with a right upper abdominal mass and abdominal pain for 3 and 1 months as chief complaints, respectively. Initially, the patient was misdiagnosed with hepatocellular carcinoma based on her symptoms and results of physical and imaging examinations. Following multidisciplinary discussion and ruling out surgical contraindications, a decision was taken to proceed with surgical intervention. Interestingly, the tumor was found to originate from the retroperitoneum and had invaded the right half of the liver and the right wall of the inferior vena cava. The operation was uneventful, and the pathological findings confirmed the tumor as an extrapancreatic SPN. The patient remained asymptomatic after 15 months of follow-up.
UNASSIGNED: Surgical treatment remains the preferred option for extrapancreatic SPN. The preoperative misdiagnosis also highlights the importance of accurate diagnosis and the development of appropriate treatment strategies for liver masses.