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

Spontaneous regression of metastatic hepatocellular carcinoma following 3 weeks of lenvatinib

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related mortality and is associated with a poor prognosis. Rarely, there is spontaneous regression of the tumour. We present a case of a middle-aged male with presumed metastatic HCC who experienced enduring regression following 3 weeks of lenvatinib, which was discontinued due to side effects. While this could represent an unusually successful response to therapy, spontaneous tumour regression or an alternative diagnosis should be considered. We discuss possible mechanisms that might explain this unusual case and advocate for tissue confirmation in select cases, where there is diagnostic doubt or when the disease pattern does not clearly follow the recognised natural history. Therefore, if regression occurs-whether spontaneous or in response to treatment-it can be better understood and subsequent therapies recommended.

Spontaneous regression of hepatocellular carcinoma: A mini-review

Spontaneous tumor regression is an extremely rare phenomenon in the oncology field. However, there are several case reports resulted in the regression of hepatocellular carcinoma (HCC) and the accumulation of clinical information and analyses of the mechanism can contribute to the development of a novel therapy. For this purpose, we have carefully reviewed 23 cases of spontaneously regressed HCC published in recent 5 years and our case. The information regarding the tumor size, tumor marker, treatments, etc., have been summarized. The mechanism of spontaneous regression has been discussed to date and presumed to be due to many factors, including hypoxia and immunological reactions. In this careful review of the 24 cases based on the clinical information, hypoxia, systemic inflammation, and both upon spontaneous regression were seen in 3, 8, and 4 cases, respectively among the 15 cases for which the information regarding the proposed mechanisms are available. Recent development of immunotherapeutic approaches in oncology shows promising results, therefore, accumulation of additional cases and analysis of mechanisms underlying the spontaneous regression of HCC are essential and could lead to the development of a new generation of immunotherapies including antibodies directed against immune reactions.

[Solitary necrotic nodule of the liver: about two cases]

Les lésions hépatiques nodulaires sont majoritairement tumorales. Le nodule nécrotique solitire du foie est rare. Le diagnostic preopératoire est difficile. Il s'agit d'une femme âgée de 43 ans qui était opérée d'un adénocarcinome du rectum métastatique au foie opéré. Le scanner abdominal de surveillance a révélé un nodule hépatique d'allure métastatique. Le second cas est celui d'un homme de 56 ans, admis pour cholécystectomie avec découverte per-opératoire d'un nodule hépatique. Dans les deux cas, le nodule hépatique était sous capsulaire et a été réséqué. L'examen anatomopathologique posait le diagnostic de nodule nécrotique solitaire du foie. Le nodule nécrotique non spécifique du foie est une lésion qui doit être évoquée, même dans un contexte néoplasique. Une caractérisation par l'imagerie et une ponction biopsie des lésions hépatiques peut être utile.

Specific imaging characteristic of solitary necrotic nodule of the liver: Marked peripheral rim-like enhancement with internal hypointensity on longer delayed MRI

OBJECTIVES

To obtain specific imaging findings of solitary necrotic nodule of the liver (SNNL) using longer delayed contrast-enhanced MRI and compare them with those of three mimic hepatic diseases.

METHODS

Sixteen patients with SNNL underwent plain and contrast-enhanced triphasic CT and multiphasic MRI with delayed time prolonged to 2 h after contrast bolus injection. Twenty-three patients with mimic lesions including seven with eight HCCs, five with five iCCs and 11 with metastatic lesions served as the control group. Those patients also received plain and multiphasic contrast-enhanced MRI. Imaging features of lesions such as peripheral wash-out time were evaluated.

RESULTS

Among the 16 SNNLs, with a prolonged delayed MRI time, the enhancement degree of tumour periphery increased gradually. When it was up to 1 h, all lesions represented moderate/marked peripheral enhancement with internal hypointensity. However, the peripheral wash-out in seven HCCs (87.5%) and all metastatic lesions except three appeared at 10 or 15 min, one iCC (20%) at 30 min and the other lesions at 1 h.

CONCLUSIONS

Longer MRI with a delayed time of 1-2 h may be useful in diagnosis SNNL, revealing the specific imaging characteristic of SNNL as pronounced peripheral enhancement with internal hypointensity.

KEY POINTS

• Longer delayed MRI plays an important role in the diagnosis of SNNL. • Characteristic imaging feature of SNNL is pronounced peripheral enhancement with internal hypointensity. • Periphery wash-out time can differentiate SNNL from mimic diseases. • Imaging findings of SNNL on routine CT and MRI are unspecific.