Presentation
Cough. Non-smoker.
Patient Data
There is a well-defined nodular opacity likely in the right middle lobe. No calcifications appreciated. The lungs and pleural spaces are clear. Cardiomediastinal contours are within normal limits.
14 x 11 mm nodule in the right middle lobe lateral segment with smooth, lobular contours, no cavitation and no calcification. A branch of the middle lobe lateral segmental bronchus terminates in the nodule. A few other punctate lung nodules noted, up to 3mm, such as in the left lower lobe, nonspecific.
Borderline 8mm right hilar lymph node. No pleural or pericardial effusion.
Moderate FDG uptake (SUVmax 5.2) is seen in the 14 mm pulmonary nodule in the right middle lobe. No other FDG avid pulmonary nodules.
Moderate FDG uptake is also seen in an 11 mm right pulmonary hilar lymph node. No other FDG avid pulmonary hilar or mediastinal lymph nodes.
Gastric FDG activity is probably within physiological limits. Small hiatus hernia noted.
No further areas of abnormally increased FDG uptake.
The patient underwent surgical wedge resection:
Macroscopy: A. Labeled "Right middle lobe wedge - frozen section". A wedge 54x24mm. On sectioning, there is a well-defined cream/grey firm lesion 15x14x10mm. This appears to abut the green inked stapled margin. The remainder of parenchyma is tan/red.
B. Labeled "Completion right middle lobectomy". Completion right middle lobectomy weighing 31 g (post-fixation) measuring 63 x 62 x 30 mm. Pleura appears grey/pale tan with areas of adherent hemorrhage. On sectioning, parenchyma appears pale tan and mildly hemorrhagic. No lesions are identified. Stapled resection margins inked green, blue and yellow which measure 65, 55 and 18 mm respectively. Bronchovascular resection margins are clear.
C. Labeled "Right lung level 4R lymph node". One potential lymph node measuring 2 mm which is surrounded by fatty tissue.
D. Labeled "R lymph node level 10". 2 pieces of potential lymph node 3 and 4 mm.
E. Labeled "Right lung station 11R lymph node", 1 potential lymph node 3 mm.
Microscopy: A. Paraffin sections confirm the frozen section diagnosis and show solid cellular tumor beneath the pleural surface. Tumor is composed of large nests of cells with a collagenous stromal reaction. The tumor cells have fairly uniform, round to oval nuclei with granular chromatin and a small to moderate amount of cytoplasm. Occasional rosette formation is evident. Mitotic figures are seen, with a mean of 1 per 10 HPF (or 2 sq mm). There is no tumor necrosis. Tumor extends into the elastic lamina of the visceral pleura, but no tumor is present on the pleural surface. No lymphovascular or perineural invasion is seen. Tumor is present at the painted margin (after removal of staples).
Tumor cells show positive immunoperoxidase staining for low molecular cytokeratin (Cam 5.2), TTF-1, chromogranin and synaptophysin. Ki67 shows a proliferative index of approximately 10%.
B. Sections show lung tissue within normal limits. A small benign intraparenchymal lymph node is present. There is no malignancy.
C. The biopsy consists of fibroadipose connective tissue. There is no lymph node. There is no malignancy.
D. Sections show lymph node with no malignancy.
E. Sections show lymph node with no malignancy.
Conclusion: A,B. Right middle lobe lung wedge resection with completion lobectomy specimens: Typical carcinoid tumor, 15 mm in size.
- mean mitotic rate 1 per 2 sq mm, no tumor necrosis
- invasion of visceral pleura (PL1)
- no lymphovascular invasion identified
- resection margins clear
- one benign intraparenchymal lymph node
- pT2
C. Right lung level 4R lymph node, biopsy: Benign connective tissue only.
D. Right level 10 lymph node, biopsy: Benign lymph node.
E. Right 11 R lymph node, biopsy: Benign lymph node.
Case Discussion
Pulmonary carcinoid tumors usually have an indolent and more benign behavior 1. Peripheral pulmonary carcinoid tumors, as in this case, are those carcinoids arising within the periphery of the lung.
Although this patient went to an 18-FDG PET instead of octreotide scanning, the lesion showed moderate uptake and guided surgeons toward resection. There was the risk of a false-negative FDG PET, which is described in up to a quarter of the carcinoid tumors 1.
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