Solitary necrotic nodule of the liver

Solitary necrotic nodule of the liver: imaging features, differential diagnosis and management

Solitary necrotic nodule of the liver (SNNL) is a rare and benign liver lesion often discovered incidentally. Despite its occurrence, the exact cause of SNNL remains unknown, with various theories proposing traumatic, infectious, degenerative or transformative origins. The variable imaging characteristics of SNNLs frequently lead to misdiagnosis as malignant tumors, prompting patients to undergo unnecessary and high-risk procedures such as biopsies and surgeries. Moreover, biopsies often yield inconclusive results due to the presence of necrotic tissue within the lesion, posing challenges for accurate histologic diagnosis. This review aims to offer guidance on differentiating SNNLs from other liver lesions using multimodality imaging approaches. It will analyze essential imaging steps that should be performed and highlight those that should be avoided to enhance diagnostic accuracy and prevent unnecessary interventions.

Solitary Necrotic Nodule of the Liver: A Benign Mimicker of Malignancy

Solitary necrotic nodule (SNN) of the liver is an uncommon and benign finding in liver pathology. Typically, it appears as a single and asymptomatic lesion, primarily located at the subcapsular region of the right lobe of the liver. Unfortunately, it is easy to mistake this benign lesion for a primary or secondary neoplastic lesion, making it a potential diagnosis pitfall for liver malignancies. The diagnosis of SNN can be difficult to determine as the imaging findings frequently lack specificity. This brings out the importance of histomorphological examination to accurately identify this lesion, and to rule out any possible malignancies. We report here the case of a 35-year-old woman with a history of squamous cell carcinoma of the cervix, who presented a solitary nodule on her liver that was falsely diagnosed as a metastatic lesion in the liver at imagery. The aim of this article is to highlight the importance of using special stains and immunohistochemical staining for diagnosing SNN and excluding any necrotic metastases of the liver. We demonstrated that the absence of a reticulin meshwork in the necrotic core should prompt consideration of a necrotic metastasis in the liver, rather than a solitary necrotic nodule.

Spontaneous hepatic rupture during late pregnancy in a patient with solitary necrotic nodule of the liver: A case report

Background

Spontaneous hepatic rupture (SHR) during pregnancy is a rare and life-threatening event, which usually occurs together with preeclampsia, eclampsia, HELLP syndrome, or liver tumors. However, SHR resulting from solitary necrotic nodule of the liver (SNNL) is extremely rare.

Case presentation

We report the case of a 32-year-old pregnant woman who presented at 33 weeks of gestation with abdominal pain and emesis. Transabdominal ultrasound and magnetic resonance imaging revealed massive hemoperitoneum and lesions in the left lobe of the liver. An emergency cesarean section was performed and the hepatic rupture was managed surgically via left lateral lobectomy. The postprocedural course was uneventful. The premature baby successfully survived, and the patient was discharged 8 days after admission without complications. Histological examination revealed a diagnosis of SNNL, which resulted in the hepatic hematoma and SHR.

Conclusion

To our knowledge, this is the first case of SHR resulting from SNNL during late pregnancy. Multidisciplinary collaboration and surgical management are important cornerstones for improving the perinatal outcomes when SHR is suspected in a pregnant patient.

Characteristics of hepatic solitary necrotic nodules on contrast-enhanced ultrasonography

Background

To summarize the characteristics of solitary necrotic nodules (SNN) in the liver observed under contrast-enhanced ultrasonography (CEUS).

Methods

Conventional ultrasonography (US) and CEUS were performed in 24 patients who were confirmed to have SNN by pathological assessment. The US data and dynamic enhancement patterns of CEUS were recorded and retrospectively analyzed.

Results

Ten of 24 patients underwent surgical resection, while the other 14 patients underwent a puncture biopsy to be confirmed as SNN. Among the 24 patients, 13 patients had a single lesion and 11 patients had multiple lesions. The largest lesion was selected for CEUS examination for patients with multiple lesions. Eleven patients presented no enhancement in all three phases, while the other 13 patients presented with a peripheral thin rim-like enhancement in the arterial phase, an iso-enhancement in the portal phase and delayed phase. However, no enhancement in the interior of the lesions was detected during three phases of CEUS.

Conclusions

SNN has characteristic findings on the CEUS, which play an important role in the differential diagnoses of liver focal lesions.

A case of solitary necrotic nodule treated with laparoscopic hepatectomy: spontaneous regression of hepatocellular carcinoma?

Solitary necrotic nodule of the liver is a rare benign lesion with a completely necrotic core and a hyalinized fibrotic capsule containing elastic fibers. The pathogenetic mechanism is still unclear. We here describe a case of SNN, whose central reticulin fibers within the nodule suggest the origin as hepatocellular carcinoma or other hepatocyte-origin tumors, treated with laparoscopic anatomical segmentectomy of the liver. A 76-year-old Japanese female, with no prior medical history and no symptom, visited our hospital with the heterogeneous hypoechoic lesion in the liver segment VI incidentally pointed out in abdominal ultrasonography. Computed tomography with contrast demonstrated a 1.1 cm sized low-density lesion with mild ring enhancement on the rim in the arterial phase. Since the possibility of malignant tumor with necrotic change could not be ruled out, she underwent laparoscopic anatomical segmentectomy of the liver. In the histological examination of the surgical specimen, the liver nodule was necrotic tissue without viable cells and signs of inflammation, which had fibrous capsule and central cystic change and showed trabecular pattern alignment of ghost cells and reticulin fibers orthogonal to the capsule. Also, the findings of chronic hepatitis were observed in the background liver.