Atypical Appendicitis Mimicking Gynecological Pathology: A Diagnostic Challenge in a Middle-Aged Woman

Introduction

Acute appendicitis, with a lifetime risk of 6.7% to 8.6%, is a leading cause of acute abdomen worldwide [1,2]. Delayed diagnosis increases the risk of severe complications such as perforation, peritonitis, and sepsis, thereby raising morbidity and mortality rates [3,4]. The incidence of appendicitis is influenced by factors such as age, sex, and seasonal variation. Although men have a slightly higher lifetime risk (8.6% vs 6.7%) [3,4], women experience higher misdiagnosis rates – estimated at 30% to 40% – largely due to anatomical overlap between the appendix and pelvic organs [4]. Appendicitis can occur at any age but is most often diagnosed between 5 and 45 years, with a peak incidence between 15 and 19 years [3,5].

Diagnosis usually is straightforward in patients with classic migratory periumbilical pain that later localizes to the right iliac fossa, accompanied by anorexia, nausea, vomiting, low-grade fever, or diarrhea [2,6]. However, atypical presentations – most often due to anatomical variations such as a pelvic appendix – can mimic gynecological or urinary symptoms because of the appendix’s proximity to the adnexa and bladder, particularly in women of reproductive age [7]. In such cases, reliance on imaging and laboratory results may be misleading. Up to one-third of female patients are initially misdiagnosed with other conditions such as ovarian cysts, pelvic inflammatory disease (PID), or urinary tract infection [8,9].

Although atypical presentations are well described, this case is unique because the patient exhibited a 2-month history of persistent suprapubic pain before acute worsening—an exceptionally chronic course rarely documented in the literature. This temporal pattern contributed substantial diagnostic ambiguity and highlights the need to reconsider appendicitis in cases of long-standing, non-specific pelvic pain.

This report addresses a critical gap by presenting a case involving a middle-aged woman with prolonged symptoms, underscoring cognitive biases in differential diagnosis. It emphasizes the importance of reassessment, clinical vigilance, and a multidisciplinary approach, while also drawing attention to the limitations of imaging modalities in diagnosing atypical appendicitis.

Case Report

CASE PRESENTATION AND ASSESSMENTS:

A 46-year-old woman was referred to the Department of Obstetrics and Gynecology at Jazan University Hospital on May 14, 2024, with a chief complaint of persistent lower abdominal pain that had been present for 2 months. The pain was continuous, insidious in onset, mainly localized to the suprapubic midline region, dull in character, non-progressive, non-radiating, and unrelated to her menstrual cycles. She reported no associated symptoms such as fever, nausea, vomiting, anorexia, urinary urgency or frequency, malaise, constipation, or diarrhea. She had experienced a few episodes of postcoital bleeding during the same period. Her menstrual cycles were regular, and she had never undergone a cervical smear test. She had 2 children, both delivered vaginally, and a recent pregnancy test result was negative. She had been using a copper intrauterine contraceptive device (IUCD) for the preceding 10 years, which had been removed 1 month before presentation. The remainder of the systemic evaluation was non-contributory.

The patient had no significant medical or surgical history and was not taking any regular medications. She reported no known drug allergies. She denied the use of tobacco, alcohol, or recreational drugs. There was no relevant family history of chronic illness or malignancy.

Before referral to Jazan University Hospital, the patient had undergone an initial evaluation on April 22, 2024, by a gynecologist at a private clinic in Jazan. At that time, the pain was mild, and she had no associated symptoms. Laboratory investigations, including a urine dipstick test and complete blood count (with white blood cell count), showed results within normal ranges. Considering her history of an IUCD in situ and postcoital bleeding, a presumptive diagnosis of PID was made. The IUCD was removed, and she was treated with a 14-day empirical course of oral doxycycline and metronidazole. Despite completion of the antibiotic regimen, her pain persisted with minimal improvement. Because of continuous abdominal pain, she consulted a radiologist. Abdominal scanning demonstrated a prominent appendix without signs of inflammation. Her complete blood count results (including white blood cell count) remained within normal limits, and a urine culture showed no microbial growth. In the absence of any alarming clinical or laboratory findings, she was advised to adopt a conservative wait-and-watch approach and to seek medical attention if symptoms worsened.

Finally, when the patient experienced no pain relief, she was referred to the Gynecology Clinic at Jizan University Hospital. Her primary complaint remained moderate pain localized to the suprapubic region, without any new symptoms. On physical examination, she was afebrile and well hydrated, with a pulse of 88 bpm and blood pressure of 110/70 mmHg. Her abdomen was soft, with mild midline suprapubic tenderness; assessment revealed no McBurney’s point tenderness, rebound tenderness, or abdominal rigidity. On speculum examination, the cervix appeared inflamed with mild vaginal discharge. Bimanual palpation revealed an anteverted uterus of normal size, freely mobile and non-tender, without palpable adnexal masses and without adnexal or cervical tenderness.

A repeat pelvic ultrasound was performed, which revealed a uterus of normal size, shape, and echotexture in an anteverted position. The endometrium was smooth and regular, measuring 5 mm. Bilateral anechoic, unilocular, thin-walled ovarian cysts were present; the right ovarian cyst measured 2.96×3.04 cm (Figure 1), and the left measured 2.56×2.29 cm. The patient was advised to undergo a cervical smear and to maintain adequate hydration, use analgesics as needed, and consult both a general surgeon and a urologist to rule out non-gynecological causes of her symptoms. She was also advised to return for follow-up after her next menstrual period to reassess the ovarian cysts. The following day (May 15, 2024), she developed acute, severe, throbbing abdominal pain that localized and shifted to the right iliac fossa. She presented to the emergency department. She remained afebrile and denied associated symptoms, and her white blood cell count remained within normal limits.

TREATMENT MODALITY:

A contrast-enhanced computed tomography (CT) scan of the abdomen and pelvis revealed bilateral simple ovarian cysts, measuring 3.2 cm on the right and 2.7 cm on the left (Figure 2). The appendix was minimally distended, with a maximal diameter of 6 mm and minimal surrounding fat stranding (Figure 3). Although equivocal, these findings were suspected to indicate early inflammation and thus warranted prompt surgical consultation. Due to the progression and localization of pain in the right iliac fossa, and given the limitations of imaging in atypical presentations, the surgical team proceeded with emergency laparoscopic appendectomy based on strong clinical suspicion. Intraoperatively, an inflamed pelvic appendix without perforation was identified and removed. Histopathological examination revealed features of early acute appendicitis with fibrous obliteration, confirming the diagnosis.

FOLLOW-UP AND OUTCOMES:

After surgery, the patient was prescribed analgesics and antibiotics. Postoperative healing was uneventful, and she was discharged in good condition with complete resolution of her symptoms. At the 6-month follow-up, she remained asymptomatic without recurrence of abdominal pain or related complications. A timeline of the patient’s care is provided in Table 1.

Discussion

Appendicitis is often misdiagnosed, particularly in women, due to variable presentation and symptom overlap with gynecological conditions. Studies indicate that more than one-third of women with appendicitis are initially diagnosed with an alternative pelvic disorder [10–12]. The present case similarly demonstrates how non-classic presentations and inconclusive imaging findings can be misinterpreted as ovarian pathology. Overall, atypical appendicitis may closely mimic gynecological conditions in reproductive-age women, often resulting in diagnostic delays.

Persistent lower abdominal pain with an inconclusive initial workup, as in the present case, illustrates the diagnostic complexity when a middle-aged woman exhibits symptoms resembling gynecological disease. Pelvic appendices may present with suprapubic pain and can easily be mistaken for urinary infection, PID, or ovarian cysts, delaying accurate diagnosis [10]. This overlap is largely explained by the anatomical position of a pelvic appendix, which lies close to the adnexa, uterus, and bladder. Inflammation in this region can cause referred suprapubic pain and mimic gynecological or urinary pathology, leading to diagnostic confusion. A lack of response and persistence of symptoms despite appropriate antimicrobial therapy for PID should prompt re-evaluation of the differential diagnosis. Persistent symptoms and inconclusive imaging warrant timely reassessment to avoid missed or delayed diagnosis.

A key cognitive error in the present case was anchoring bias – overreliance on the initial diagnosis of PID despite evolving symptoms and lack of clinical improvement. This bias contributed to delays in considering a broader differential diagnosis and initiating cross-specialty consultation [8,11,12]. Additionally, the availability heuristic may have influenced clinical reasoning, given that gynecological causes of lower abdominal pain are more frequently encountered in women of this age group. This reliance on familiar diagnostic patterns can unconsciously limit clinical perspective and lead to underrecognition of less common but critical conditions (e.g., appendicitis). To mitigate such biases, standardized clinical checklists, structured reassessment of persistent or atypical symptoms, and regular multidisciplinary review have been shown to broaden diagnostic thinking and reduce error. Multidisciplinary collaboration and clinical vigilance are essential to minimize cognitive biases and ensure timely intervention.

Although ultrasound and CT are essential diagnostic components during the evaluation of abdominal pain, their utility may be limited in certain clinical scenarios. In the present case, the ultrasound findings were non-specific, revealing only bilateral simple ovarian cysts. CT scans repeatedly showed bilateral ovarian cysts (Figure 2), which initially distracted from the subtle appendiceal changes. The appendix appeared only minimally distended at 6 mm in diameter, with slight surrounding fat stranding – findings that were equivocal and did not meet established radiologic criteria for appendicitis. This scenario demonstrates how adnexal findings may bias interpretation and delay recognition of early or atypical appendiceal pathology. Importantly, both ultrasound and CT, despite their widespread use, are not immune to false negatives, particularly in early or atypical presentations. Ultrasound sensitivity for atypical appendicitis is approximately 47%, due to operator dependency and factors such as body habitus; complementary clinical judgment is essential [10]. CT, although more accurate, may miss instances of subtle radiologic features or anatomical variation. Overreliance on imaging and laboratory results, without the integration of clinical judgment, can contribute to diagnostic delays. When appendicitis remains within the differential diagnosis but imaging and laboratory findings are inconclusive, early diagnostic laparoscopy is recommended to achieve timely diagnosis and prevent complications [2,5,7,12–14]. Clinicians should recognize the inherent limitations of imaging modalities and ensure sound clinical judgment to achieve accurate diagnosis.

Ultimately, this case highlights the importance of adaptive diagnostic strategies in the evaluation of persistent lower abdominal pain, particularly among women with atypical symptoms. Approaches such as structured diagnostic checklists, repeated clinical reassessment, and multidisciplinary algorithms (e.g., joint gynecology–surgery assessment within 24 h for persistent pain) may help avoid anchoring bias and reliance on inconclusive imaging results [12,14].

Conclusions

In a broader context, this case underscores the need for health systems that promote re-evaluation of unexplained, persistent symptoms and facilitate intradepartmental communication to expand the range of differential diagnoses. Institutions should consider adopting electronic health record alerts for patients with more than 48 h of unresolved abdominal pain to trigger automatic surgical review, reduce morbidity based on existing models, and ensure safe care for patients with atypical abdominal presentations.