Clear Cell “Sugar” Tumor of the Lung: Benign or Malignant?

Abstract

Clear cell ''sugar'' tumors of the lung are rare pulmonary tumors. This case study illustrates a patient who was found to have a persistent nodule in the left-upper lobe of the lung. Positron emission tomographic scanning showed mild-moderate 18-fluorodeoxyglucose uptake. Based on these findings, a video-assisted resection of the tumor was undertaken. The mass was identified histologically, as a clear cell ''sugar'' tumor of the lung. This case report discusses the benign versus malignant nature of this rare tumor.Key words: Clear cell sugar tumor -Rare tumor -Lung tumor -Incidentaloma L ung cancer is one of the leading causes of cancer death in industrialized countries. Early discovery is an important factor for survivability. With only a limited number of cases reported, 1 clear cell (sugar) lung tumors are extraordinarily rare. These particular lung tumors have been described as benign neoplasms that have a considerable amount of intracellular glycogen among other diagnostic features. The characteristic presence of such a high amount of glycogen has led to these tumors as often being referred to as simply, sugar tumors of the lung. The purpose of this report is to add to other reported cases of this rare pulmonary lesion, through a comprehensive literature review. The goals are to inform physicians of this rare entity, and to discuss how these tumors can be confused with malignant tumors. CaseA 39-year-old, well-developed female presented with evidence of a persistent nodule located in the left-upper lobe of the lung. A whole body positron emission tomographic/computed tomography (PET/CT) showed the nodule measuring approximately 1.1 cm 3 1.0 cm in size along with persistent ground glass type infiltrate. The 18-fluorodeoxyglucose uptake was positive. The nodule was also shown to be changing with serial films, with an increase in size. The structural exam was normal except for paravertebral tissue fullness around T2 to T5. It was recommended that she undergo videoassisted thoracoscopic resection of the lesion. A wedge resection was carried out and the lesion was successfully removed alongside normal surrounding parenchyma. Frozen sections showed evidence of inflammatory cells surrounding the nodule, but no evidence of malignancy. During the operation, both the lesion and the lung parenchyma were opened and aerobic, anaerobic, and acid-fast cultures were obtained. The rest of the lung appeared healthy with no pleural effusions or any other abnormalities. The operation was well-tolerated and the patient recovered completely and continued to do well on postsurgical cardiothoracic surgical clinic visits. Final pathology was consistent with benign sugar tumor (Fig.

Clear cell sugar tumour: a rare tumour of the lung

“…It was first described by Liebow and Castleman in 1963 and has since been reported in as many as 50 cases in English literature . They are known as sugar tumours as their cytoplasm contains abundant glycogen . The 2015 World Health Organization Classification of Tumours of the Lung, Pleural, Thymus and Heart identified a group of tumours with perivascular epithelioid origin, termed PEComatous tumours .…”

“…Definitive diagnosis is established by demonstrating immunoreactivity for human melanoma black‐45 (HMB‐45) and S‐100 protein, with no reactivity for cytokeratin 7 or epithelial membrane antigen . HMB‐45 is a monoclonal antibody that binds antigen present in melanocytic tumours and clear cell tumours .…”

“…This protein family can serve as a marker for melanomas, peripheral nerve sheath tumours, clear cell tumours and epidermal differentiation. The CCST cells are also positive for melan‐A, micropthalmia transcription factor, tyrosinase and NKI/C3 …”

“…2 They are known as sugar tumours as their cytoplasm contains abundant glycogen. 3 The 2015 World Health Organization Classification of Tumours of the Lung, Pleural, Thymus and Heart identified a group of tumours with perivascular epithelioid origin, termed PEComatous tumours. 4,5 PEComas can be benign or malignant and can be found in other sites, including the female genital and gastrointestinal tracts.…”

“…2 Definitive diagnosis is established by demonstrating immunoreactivity for human melanoma black-45 (HMB-45) and S-100 protein, with no reactivity for cytokeratin 7 or epithelial membrane antigen. 3 HMB-45 is a monoclonal antibody that binds antigen present in melanocytic tumours and clear cell tumours. 6 The S-100 protein is normally present within neural crest cells, chrondrocytes, adipocytes, myoepithelial cells, macrophages, Langerhans cells, dendritic cells and keratinocytes.…”