90 Chapter 6 Distribution of Loose Fragments in Relation to Cutting Order Five cases with malignant loose fragments were found in block 1, 18 cases in block 2, 19 cases in block 3, and 17 cases in block 4. The total number of elds with malignant loose fragments in all blocks was 244; in the blocks 1 to 4 was 16, 62, 82, and 84, respectively. Thus 93% of the malignant loose fragments were present in the blocks 2 to 4 (228/244). The mean number of malignant loose fragments for blocks 1 through 4 was 0.36, 1.44, 1.86, and 1.95, respectively. For benign loose fragments the mean number for blocks 1 through 4 was 0.11, 0.11, 0.13, and 0.25, respectively; with absolute numbers 5, 5, 6, and 11, respectively. The number of elds with malignant loose fragments differed signi cantly between the blocks (P = 0.003). Post hoc comparisons revealed signi cant differences between block 1 ( rst cut) and blocks 3 and 4 (second cut) (P = 0.006 and 0.015, respectively, after Bonferroni correction) but not between blocks 1 and 2 (deeper cut) (P = 0.093, after Bonferroni correction). The number of malignant loose fragments was higher when the specimen was cut fresh in comparison with specimens cut after formalin xation, and also signi cant when comparing loose fragments numbers in blocks 1 versus 3 (P = 0.042), but not for the blocks 1 versus 2 (P = 0.37) or blocks 1 versus 4 (P = 0.79). For benign loose fragments no signi cant difference was identi ed between the 4 blocks (P = 0.23). The association of loose fragments with the clinicopathologic parameters revealed a statistically signi cant greater number of loose fragments between blocks 1 and 4 in AdC compared with SqCC (P = 0.028), but not between block 1 and blocks 2 and 3 (P = 0.24 and 0.32, respectively). Of the 12 cases without loose fragments, 6 were AdC (24% of the AdC cases) and 6 were SqCC (46% of the SqCC cases), but these differences were not signi cant (P = 0.16). Regarding the 26 AdC, the number of loose fragments in the 4 micropapillary predominant carcinomas was statistically signi cant higher from the other AdC cases between blocks 1 and 2 (P = 0.016). No differences were seen when the 5 cases with a secondary micropapillary component or the 12 cases with any micropapillary component were compared with the other AdC. A statistically signi cant difference was not seen with regard to surgical specimen type, including VATS versus thoracotomy resection when comparing block 1 with blocks 2 to 4 (P = 0.78, 0.056, and 0.61). Age, sex and tumor diameter were also statistically insigni cant. Discussion Surgical pathologists are familiar with the phenomenon of tissue oaters, not only as extraneous tissue fragments sitting on top of tissue, but also as “loose” fragments of tissue elsewhere on the slide. These pieces of tissue may originate from grossing tables, prosecting instruments, water baths, microtome blades, or tissue stainers. We were not concerned with tissue oaters of these sorts, but rather detached fragments of malignant or benign cells originating from the lung specimen. Dis- placed tumor cells
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