PubMed · 6007578
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Y Kuwata. 1966-05-20. [Studies on malignant goiter. 2. Electron microscopic study].. https://doi.org/10.1507/endocrine1927.42.2_158
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Fetal mouse lung before gestation day 17 shows unique sensitivity to causation of rapidly growing tumors by N-ethylnitrosourea (ENU). Since mouse lung tumors present a mutated K-ras oncogene, we hypothesized that this special susceptibility might reflect an unusual vulnerability of the K-ras gene. Of the lung tumors caused by ENU exposure of BALB/c mice on gestation day 14, 8/25 had a codon 12 mutation in K-ras, vs 4/25 in codon 61. Of 15 tumors after day 16 exposure, three had codon 12 and four codon 61 changes. Tumors from day 18 exposure had only codon 61 mutations (11/16), all A:T to G:C changes (CGA). By contrast, codon 12 (GGT) changes included G:C to T:A, to A:T, and to C:G. These results show significant (P<0.01) shift in the sensitivity of particular K-ras codons to ENU mutation, during fetal mouse lung maturation. In a test of a possible relationship to expression of K-ras, K-ras p21 was measured in lungs of fetal mice, and found to increase markedly on day 18 in comparison to days 14 and 16. Both alkylation of DNA and base damage due to reactive oxygen species are postulated as mechanisms for mutation by ENU, whose efficacies vary with state of fetal lung maturation and K-ras expression.
The breast is an uncommon site for metastasis from extramammary primaries. A 43-year-old woman presented with a lump in the left breast. A tumour with atypical microcalcifications was seen on the mammogram. Needle aspiration cytology revealed adenocarcinoma cells. The final histological diagnosis was papillary adenocarcinoma with psammoma bodies, probably secondary to an ovarian carcinoma. A bilateral carcinoma of the ovaries was subsequently diagnosed and treated. A mammary tumour with an atypical growth pattern and the absence of in situ carcinoma should always prompt the pathologist to considering the possibility of a metastatic tumour even though this is a rare occurrence. Earlier recognition of metastatic tumours to the breast may result in initiation of appropriate therapy and will preclude unnecessary surgical procedures.
The retinal pigment epithelium (RPE) can undergo reactive hyperplasia and metaplasia following a variety of ocular insults. However, true neoplasms of the RPE are rare. We report a case of a papillary adenocarcinoma of the RPE arising in the blind staphylomatous right eye of a 79-year-old woman with a long history of bilateral posterior staphylomas who was seen with increasing pain and exophthalmos of the right eye. Findings from ultrasonography and computed tomography demonstrated linear calcification consistent with osseous metaplasia of the RPE. Progression of the exophthalmos and worsening exposure keratitis led to enucleation of the eye. Gross pathology showed a 79-mm-long globe. Histopathologic findings revealed a largely amelanotic papillary adenocarcinoma arising from the RPE. Positive immunoreactivity for cytokeratin supported the epithelial origin of the tumor. Adenocarcinoma of the RPE is rare but may develop in a blind eye.