A case report of an unusual non-mucinous papillary variant of CPAM type 1 with KRAS mutations

Abstract

Background: congenital pulmonary airway malformation (CPAM) is the most frequent congenital lung disorder. CPAM type 1 is the most common subtype, typically having a cystic radiological and histological appearance. Mucinous clusters in CPAM type 1 have been identified as premalignant precursors for mucinous adenocarcinoma. These mucinous adenocarcinomas and the mucinous clusters in CPAM commonly harbor a specific KRAS mutation. Case presentation: we present a case of a 6-weeks-old girl with CPAM type 1 where evaluation after lobectomy revealed a highly unusual complex non-mucinous papillary architecture in all cystic parts, in which both mucinous clusters and non-mucinous papillary areas harbored the known KRAS mutation. Conclusions: we found that a KRAS mutation thought to be premalignant in mucinous clusters only, was also present in the other cyst lining epithelial cells of this unusual non-mucinous papillary variant of CPAM type 1, warranting clinical follow-up because of uncertain malignant potential.

Selection of potential targets for stratifying congenital pulmonary airway malformation patients with molecular imaging: is MUC1 the one?

“…However, we only identified this gene twice in our search. This is probably due to the fact that DICER1 is associated with CPAM type 4 [75,76] and KRAS is mostly associated with CPAM type 1 and type 2 [17,27,28,[29][30][31]. Although this should be taken into consideration, DICER1 mutations appear to be less relevant for this purpose since these mutations are less common in CPAM (and AIS) compared to KRAS mutations.…”

“…KRAS mutations were found in all mucinous proliferation tissue, whereas the surrounding healthy lung tissue did not contain this mutation [24][25][26]. Specifically, KRAS mutations located on exon 2 G12V and G12D were found in both CPAM and mucinous AIS [17,25,[27][28][29][30][31]. Because KRAS mutations found in lung tissue in adults supports the diagnosis of malignancy, we hypothesised that KRAS-positive CPAM patients (i.e.…”

Atypical antenatal presentation of an unusual nonmucinous papillary variant of giant congenital pulmonary airway malformation masquerading as congenital diaphragmatic hernia with volvulus

“…This case bears a lot of resemblance with the only reported case of this variant earlier this year by Koopman in a lobectomy specimen of a 6-weeks-old female child. [ 4 ] Both these fetuses had their first presentation at 20 weeks and early onset of hydrops. The similarity between the postnatal Computed tomography pictures of the reported case and ultrasound pictures of the present case suggests the typical huge cystic pattern with early onset of hydrops.…”