Targeted immunotherapy has markedly improved the survival of melanoma patients. We report the case of a melanoma patient who developed a collagenous colitis under an anti-PD1 regimen. A 68-year-old woman was treated for a stage IV melanoma. An anti-PD1, pembrolizumab, was introduced after the failure of a first-line therapy with an anti-CTLA4. At cycle 14, pembrolizumab was interrupted because of grade 3 diarrhea. Histologic analysis of colon mucosa showed a thickened apical subepithelial collagen layer with irregular collagen deposition of more than 25 µm thickness. Budesonide 9 mg/day and cholestyramin 8 g/day were then introduced, leading to a decrease in the number of stools to grade 2. Because of the prognosis of the disease, the efficacy of pembrolizumab in this patient and the lack of other efficient treatments, pembrolizumab was restarted, with no worsening of the diarrhea after a follow-up of 8 weeks. In the era of immunotherapy, a new type of drug-induced colitis has emerged because of monoclonal antibodies targeting immune checkpoints such as CTLA-4 and PD1. Gastrointestinal tract immune-mediated adverse effects are now well described with ipilimumab. To the best of our knowledge, this is the first report of a collagenous colitis in a patient treated with pembrolizumab, thus suggesting a new mechanism of toxicity. Classically, collagenous colitis first-line treatment is based on discontinuation of the suspected treatment. However, there may be a strong benefit to maintaining an anti-PD1 regimen in our patients. In this case, symptomatic management associated with budesonide and cholestyramin enabled continuation of pembrolizumab.

Renal echinococcosis is relatively uncommon compared to liver and lung localizations. Kidney involvement represents 4% of confirmed cases of hydatid disease. We reviewed the clinical findings of a personal series of renal hydatidosis with emphasis on diagnostic and therapeutic issues. A total of 178 renal cysts were collected over a period of 33 years from 1963 to 1996. Clinical, radiologic and laboratory data are analyzed. Radiologic exploration has had an interesting evolution, with the appearance of ultrasonography and computed tomography. Diagnostic accuracy has been greater since the availability of ultrasonography and immunologic studies. Their contribution to the diagnosis of renal hydatid disease is important. We try, with our experience of ultrasonography in the matter of renal hydatid cysts, to underline the role of this exploration. The treatment of hydatid cyst of the kidney is surgical. Renal-sparing surgery, cystectomy plus pericystectomy, is possible in most cases (75%). Nephrectomy (25% of cases) must be reserved for destroyed kidneys resulting from aged cysts opening into the excretory cavities and complicated by renal infection. Whether conservative or radical, the first surgery performed is cystectomy, with germinate membrane removal after controlled evacuation and opening of the cyst, making the subsequent steps of surgery easier.

No abstract