Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is a drug reaction commonly related to eosinophilia, from uncertain epidemiology, and without consensus for diagnosis and treatment globally. It presents a great challenge in its management and is characterized by fever, lymphadenopathy, skin rash, and multisystemic involvement. An aggressive and difficult-to-manage clinical case is presented in a 50-year-old man with chronic kidney disease due to diabetes mellitus type 2 and systemic arterial hypertension, who developed an unusual variant similar to DRESS and Stevens–Johnson syndrome (SJS) overlap secondary to allopurinol, with skin manifestations without eosinophilia, but fulfilling clinical and laboratory criteria for DRESS and SJS syndrome.

We present the case of a 7-year-old male patient who came to the emergency department with symptoms of expansive and oppressive holocranial headache, in addition to nausea, vomiting and diplopia, ataxia, and right brachial hemiparesis at late phase. A skull contrast-enhanced nuclear magnetic resonance was performed, resulting in a lesion located at the level of the pineal gland parenchyma, which was subsequently biopsied and the diagnosis of mixed germ cell tumor with immature teratoma and yolk sac tumor components was confirmed.

Large cell carcinoma of the lung with null-immunophenotype (LCC-NI) is a diagnostic entity that is especially uncommon now as it does not have any type of cell differentiation or its own molecular alterations. It presents an exceptional diagnostic challenge; indeed, the diagnosis is only possible with complete surgical excision and adequate immunohistochemical and molecular studies. We report the case of a 69-year-old male, with a history of long-term smoking who presented with pleuritic pain. A tumor in the upper lobe of the right lung was detected and removed by lobectomy. Histopathology revealed a neoplasm with large cell morphology without any specific immunophenotype, molecular or genomic rearrangements through next-generation sequencing (NGS) studies, which was diagnosed as LCC-NI.

A 56-year-old woman debuted with a palpable painless mass in the anterior thorax wall at the level of the second and third right parasternal intercostal space, which progressively increased in size over 5 months accompanied by localized skin rash, mild dyspnea and chest pain when changing position. Imaging studies showed a soft tissue mass measuring 75 × 62 mm and a density of 34 Hounsfield Units that had caused the lysis of the costal arches and grew expansively towards the anterior mediastinum, without identifying mediastinal adenopathies only by this imaging method. Core biopsy was performed, which was initially diagnosed as histiocytic sarcoma (HS); however, when the diagnostic panel was expanded to include molecular and NGS studies, the final diagnosis was anaplastic large cell lymphoma with ALK::ATIC fusion. Here, we report a very rare neoplasm with unusual clinical presentation, histopathology and molecular features.