Lung carcinoid tumor in a known case of mycosis fungoides: a case report

 INTRODUCTION: Lung neuroendocrine tumors (NETs) account 1 to 2 percent of all lung cancers. They include four pathological subtypes; two of them are typical and atypical carcinoids. Unlike peripheral carcinoids, centrally located tumors may present with dyspnea, wheezing and pneumonia. Mycosis fungoides (MF) is the most common form of cutaneous T-cell lymphoma (CTCL). One of its variants is Poikilodermatous, a rare form of CTCL.The article describes a patient with lung NET who is a known case of MF. CASE PRESENTATION: Our patient is a 33-year-old woman with a 4-day complication of chest pain and dyspnea. She had a history of poikilodermatous MF with feature of mottled hypo- and hyper- pigmented, pruritic lesions; shehad received PUVA as a treatment. In lung examination crackle, egophony, diminished vesicular breath sound in LUL were noticed.laboratory tests, computed tomography scan, bronchoscopy, transbronchial biopsy and BAL were done. Finally, microscopic examination of the mucosal mass which was detected in LUL.B confirmed typical carcinoid tumor through the observation of rare mitosis count and no necrosis. For medical treatment fiberoptic bronchoscopy, rigid bronchoscopy and cryotherapy were done.  DISCUSSION: MF is generally a disease of older adults and it is usually in men but poikilodermatous form can present at a younger age. One of the presentation of MF is pulmonary problem such as pneumonia and pulmonary involvements by CTCL which demonstrate poor survival but lung cancer is a rare manifestation so this topic highlights the importance of thoracic imaging in patients with CTCL referred with respiratory symptoms. Pulmonary involvements in MF are often presented as pneumonia just with an infectious cause but in our patient the main cause of pneumonia was obstruction due to carcinoid tumor. CONCLUSION: According to a study accomplished in 2016, a relation was found between treatment of primary lung cancer (adenocarcinoma/ non-small cell lung cancer) and disappearance of MF skin lesions .It is possible that in our patient, the MF skin patches resolve after complete treatment of lung carcinoid (as a lung NET and non-small cell carcinoma). By doing more researches, it is possible to find a stronger relationship between these two issues.

Keywords:

Lung NETs , Lung carcinoid tumor , Mycosis fungoides