S² segmentectomy of the right upper lobe: an uncommon but very useful segmentectomy

Compared to lobectomy, performing a segmentectomy needs more experience and anatomical knowledge, in particular atypical segmentectomies like S² resection. It is considered an uncommon but very useful procedure for the treatment of patient with early stage lung cancer in the right upper lobe. Here, we present two cases of patients with different anatomies of hilar structures in the S² segment of the right upper lobe. Case 1: an 82-year-old male patient came to our attention for a chest CT-scan finding of a 13 mm solid nodule in the S² segment of the right upper lobe. The patient was in follow up and no regression of the lesion was seen in the last CT scan. As we considered the lesion highly suspicious of early stage lung cancer, a surgical excision was proposed. So, a right S² segmentectomy by minimally invasive approach was carried out. Case 2: a 42-year-old female patient presented to our attention for a chest CT-scan finding of a 20 mm mixed-ground-glass opacity (GGO) in the S² segment of the right upper lobe. The patient was in follow up and no regression of the lesion was seen in the last CT scan. As we considered the lesion highly suspicious for a tumour, a surgical excision was proposed. A right S² segmentectomy by minimally invasive approach was performed. The post-operative course was uneventful in both patients. Final histopathological examination revealed an invasive mucinous adenocarcinoma of the lung, staged as pT1bN0M0 for the case 1 and an invasive papillary adenocarcinoma of the lung, staged as pT1bN0M0 for the case 2. S² segmentectomy is an uncommon, demanding, but very useful surgical procedure. The most difficult part lies in how to identify a recurrent A² and the right B². A clear understanding of different anatomies is critically important to complete a successful procedure.