Reportability--Appendix: Is the appendix the primary site for a low grade mucinous appendiceal neoplasm (LAMN) with diffuse peritoneal dissemination? See discussion.
MP/H/Histology--Thyroid: What is the histology code for primary site of thyroid cancer with the histology of papillary thyroid carcinoma, classical and oncocytic type?
Reportability--Ovary: Is micropapillary serous carcinoma (MPSC) of the ovary reportable? What are the differences between “noninvasive" and “low malignant potential?" See discussion.
Seq no-central--Brain and CNS: How should subsequent tumors be sequenced when the patient has a history of a brain tumor, with no information on the behavior of the brain tumor? According to the sequencing rules, it appears some assumption must be made regarding the behavior of the brain tumor.
Surgery of Primary Site--Breast: Is the surgery code 42 or 52? Does it matter that the procedure states no axillary LN, but the pathology found 2 additional LN? See discussion.
MP/H Rules/Multiple primaries--Breast: Does rule M10 apply in this situation?
L breast biopsy = INVASIVE DUCTAL CARCINOMA
L breast simple mastectomy = 2.0 cm INVASIVE DUCTAL CARCINOMA with an incidental finding of separate 1.0 cm INVASIVE LOBULAR CARCINOMA; pathologist specifically states the tumors are morphologically different. The tumors are both pure Ductal/pure Lobular.
Surgery of Primary Site--Pleura: How is this field coded if the patient underwent an exploratory thoracotomy with partial decortication that excised some, but not all, of the pleural mesothelioma tumors? See Discussion.
Reportability--Skin: Is this reportable? If so, what is the correct histology code? The pathology report says, " bx of 0.7 x 0.5 cm gray-pink papule on tan-pink skin of left inferior centra malar cheek revealed invasive SCC of skin, signet ring cell type, invading papillary dermis; LVI neg; "findings are diag of SCC exhibiting the rare signet ring histologic subtype"; deep margin positive for tumor but peripheral margins clear;".