Background: Colorectal cancer represents one of the most common neoplastic diseases worldwide, making it a frequent focus in routine pathological analyses. Visualizing complex three-dimensional (3D) structures, such as nerves within tumors, requires thick tissue sections, which necessitates the use of optical tissue-clearing methods to achieve transparency. However, following tissue clearing, samples typically require advanced imaging techniques such as light-sheet and two-photon confocal microscopy, which are usually unavailable in standard histological laboratories. Objective: We aimed to demonstrate how a well-established tissue-clearing approach can be adapted for use in a routine histological laboratory, enabling a robust 3D visualization of nerve fibers in samples of both normal human colon and colon cancer tissues. Methods: We modified the “clear unobstructed brain/body imaging cocktails” method, originally developed for whole-brain imaging in mice, and applied it to human colon tissue samples measuring approximately 10 mm3, a standard size typically processed in pathological laboratories. Results: Our protocol, which integrates a tissue-clearing technique, enabled reliable immunofluorescent visualization of colonic nerve fibers labeled with anti-β3-tubulin antibodies. The labeled nerve fibers could be observed using a standard epifluorescence microscope, and high-quality 3D reconstructions were generated through a simple image analysis approach using the open-source software ilastik, which eliminates the need for confocal microscopy. Conclusion: The proposed steps provide a valuable method for researchers to visualize complex 3D structures, such as neural cells and processes, in both normal and tumor-transformed tissue settings.

Low grade fibromyxoid sarcoma (LGFMS) is an uncommon variant of fibrosarcoma with high risk of local recurrence, immense metastatic potential and frequently protracted period between tumour presentation and metastasis. This unusual malignancy rarely affects the region of the head and neck which makes cases of laryngeal LGFMS extremely infrequent. To date, LGFMS of the larynx has been scatteredly mentioned in the literature. Neither incidence nor causes and risk factors for laryngeal LGFMS have been clarified so far. To the authors’ knowledge, this is the first case report that discusses the clinical course, imaging diagnosis, histopathological evaluation and surgical approach to radiation-induced laryngeal LGFMS.We present a case of a 70-year-old man who developed a LGFMS after previous radiotherapy (RT) for squamous cell carcinoma (SCC) of the larynx. The latency period between the time of radiation exposure and the diagnosis of LGFMS was twenty-seven months. After re-confirming the diagnosis with second biopsy and extensive imaging evaluation the patient was subjected to an open partial resection of the larynx. Owing to the rarity of the tumour, there is no established protocol with follow-up recommendations.This case highlights the importance of considering the RT history of the patient in order to monitor radiotherapy-related complications, including the occurrence of LGFMS.

Background and Clinical Significance: Blue nevi are a dubious pigmented lesion. While somewhat common throughout the population, they are significantly less common than other melanocytic neoplasms, and both their morphology and development bring them closer to true hamartomas than neoplasms. An exceedingly rare occurrence is the development of melanoma from a preexisting blue nevus. This nosological unit, defined as melanoma arising in a blue nevus, also known as malignant blue nevus, blue naevus–like melanoma, melanoma ex-blue naevus, and melanoma mimicking cellular blue naevus, is required to either originate from an area of previously excised blue nevus or have a blue nevus remnant adjacent to it. Due to the spindle cell morphology of melanoma arising in blue nevus, the terminology is often misused by some authors to include spindle cell melanomas, which exhibit a distinct pathogenesis and, although morphologically similar, have differing molecular profiles as well. Case presentations: The following manuscript discusses comparative morphological features in a case series of blue nevi and melanoma arising in blue nevi. Discussion: Blue nevi present with unique morphological features, with melanomas originating from them having a unique molecular pathology profile, which significantly differs from other cutaneous melanomas and is closer to that of uveal melanomas.

Enteric nervous system – a historical review and contemporary aspects

Background and Clinical Significance: Prostatic malignancies are amongst the leading malignancies in incidence. They represent a mixed group of conditions, predominantly characterized by adenocarcinomas, which are themselves predominantly acinar. Case Presentation: Herein, we present a morphological case report of a 73-year-old male who underwent transrectal ultrasound-guided needle biopsy due to elevated PSA levels (18.61 ng/mL). Histopathology of the biopsy specimen was represented by pleomorphic cells with predominantly clear cytoplasm, with relatively eccentric, pyknotically appearing nuclei with hyperchromatic chromatin and no visible nucleoli. After imaging excluded concomitant renal malignancy and confirmatory immunohistochemistry was carried out, the patient was diagnosed with renal-type clear cell carcinoma of the prostate. Conclusions: While unrecognized by the WHO due to its rarity, renal-type clear cell acinar adenocarcinoma of the prostate is a unique type of prostatic malignancy, which, due to its morphological appearance, necessitated careful differential diagnosis.

Background and Clinical Significance: Urothelial carcinoma is one of the most commonly diagnosed malignant diseases. However, it has a much more favorable prognosis than other significantly less common malignancies. This statement, however, is true only for conventional urothelial carcinomas, not for those with divergent differentiation or a special type of urothelial carcinoma. Case Presentation: Herein, we present a case report of an 80-year-old female patient with multiple predominantly cardiovascular comorbidities and vascular dementia, who presented to our institution with genital bleeding. Clinical and diagnostic tests were difficult due to patient noncooperation; however, abdominal computer tomography and cystoscopy showed an advanced tumor originating from the ventral bladder wall. Histology of the tumor showed an invasive urothelial malignancy with foci of clear-cell (glycogen-rich) variant and dispersed, pleomorphic cells, which were immunohistochemically positive for beta-human chorionic gonadotropin. Hence, the diagnosis of high-grade urothelial carcinoma with clear-cell (glycogen-rich) morphology and divergent trophoblastic differentiation was established. Patient outcome was poor. Conclusions: While conventionally having a somewhat favorable prognosis, special subtypes and divergent differentiation in urothelial carcinomas, which warrant a high-grade diagnosis are not only rare but also highly aggressive conditions. Further challenges arise in their differential diagnosis with other advanced malignancies, which can develop in adjacent organs in both genders