Bone marrow metastasis of solid tumours is a sign of advanced disease, with their frequency depending on the primary cancer site. Bone marrow metastasis of bladder cancer is an unusual presentation of the disease. We present a case of a patient with non-muscle-invasive bladder cancer, presenting with recurrent macroscopic haematuria after urinary catheterisation leading to discovery of bi-cytopenia on complete blood count. Myelogram realized after sternal bone marrow aspiration showed presence of metastatic cells immunostained for urothelial nature. The clinical course was rapidly unfavorable leading to patient's death shortly after diagnosis. metastasis of bladder cancer to the bone marrow is a highly unusual situation associated with a poor prognosis.

A superficial or deep mass in the limbs or body walls may be a sarcoma, even if it has been present for a long time. It warrants caution, as inappropriate surgery can worsen the prognosis. A superficial tumor should be evaluated with an ultrasound: if the tumor is not perfectly fatty and homogeneous, a percutaneous biopsy is necessary. Deep tumors require an MRI followed by a percutaneous biopsy. The final histopathological diagnosis must be awaited, which may include molecular biology in addition to immunohistochemistry. If it is a sarcoma or a desmoid tumor, the therapeutic strategy must be decided in a specialized multidisciplinary team meeting. Sarcomas require wide excision, ensuring healthy margins by staying well away from the lesion. In France, there is a network of specialized centers for the treatment of sarcomas (NETSARC+).

Rare breast tumors include benign or borderline entities that are often clinically and radiologically misleading. Diagnosis relies in all cases on appropriate biopsy and cross-anatomical-radiological interpretation. Optimal management requires multidisciplinary discussion. Desmoid tumors are non-metastatic but locally aggressive, infiltrative fibroblastic lesions whose management is now based on active surveillance. Idiopathic granulomatous mastitis is a chronic inflammatory mastitis, probably of autoimmune origin, which generally responds to corticosteroid treatment. Phyllodes tumor is a rare fibro-epithelial proliferation, with variable behavior depending on its histological grade, requiring complete excision with negative margins. Radial scarring, a benign sclerosing lesion, can mimic a carcinoma, and sometimes warrants excision depending on the presence of atypia. The aim in managing all these rare tumors is to limit overtreatment, while ensuring personalized follow-up.

Medical treatment of breast cancer today depends on the tumor profile. For triple-negative breast cancer, the standard treatment before surgery now combines chemotherapy and immunotherapy, significantly improving the chances of cure. In the metastatic stage, new therapies such as the antibody conjugate (ADC) sacituzumab-govitécan have substantially prolonged survival. For HER2-positive tumours, the strategy is also to treat before surgery. For metastatic forms, a new-generation ADC, trastuzumab deruxtecan, has proved its immense efficacy, becoming a benchmark. Finally, for hormone-dependent (HR+) cancers at high risk, the addition of CDK4/6 inhibitors to hormone therapy after surgery reduces the risk of recurrence. In addition, ADCs are also of interest in advanced forms, particularly for tumours known as "HER2-low".

Breast cancer accounts for approximately 24% of all new cancer cases in women worldwide and remains a major challenge for the medical community despite advances in screening and treatment. The management of axillary lymph nodes is crucial for local-regional control and tumor staging. Historically, radical mastectomy was introduced by William Halsted in the late 19th century; however, this method resulted in significant morbidity. Over time, less invasive techniques have been developed, notably sentinel lymph node biopsy (SLNB) in the 1990s, which assesses the status of axillary lymph nodes based on the sentinel node. If this node is disease-free, a complete axillary dissection can often be avoided, thereby reducing complications. SLNB is now recognized as the standard of care for patients with early-stage breast cancer without clinical nodal involvement, supported by studies such as ACOSOG Z0011 and AMAROS. However, questions remain regarding the best surgical approach for patients with specific tumor subtypes or extensive nodal involvement. This article offers an analysis of the scientific foundations of lymph node surgery, technical advancements, clinical trial outcomes, and the future prospects of increasingly personalized medicine.

Immediate breast reconstruction (IBR) following total mastectomy is now an established surgical approach that combines oncological safety with aesthetic benefits. This review discusses indications, techniques, and surgical adaptations of IBR based on breast morphology and adjuvant therapy planning. At Institut Curie, experience with over 600 reconstructions has led to refined patient selection, with an overall implant removal rate of 5.8%, dropping to 4% in "low risk" patients. Prepectoral implant placement, with or without acellular dermal matrices (ADM), has emerged as a reliable alternative to subpectoral techniques. It offers less postoperative pain, eliminates animation deformity, and significantly reduces capsular contracture. For large or ptotic breasts, skin-reducing mastectomy or two-stage reconstruction enhances outcomes.

Histopathological examination is a cornerstone in the diagnosis, prognostic stratification, and therapeutic planning of breast cancer. It combines morphological, immunophenotypic, and molecular data to guide clinical decision-making. This article provides a comprehensive overview of the main histological types, technical modalities, and conventional and emerging biomarkers in breast cancer pathology. Breast carcinomas are categorized into in situ (DCIS, LCIS) and invasive forms. The most frequent invasive types are invasive carcinoma of no special type (NST) and invasive lobular carcinoma (ILC). Rare histologic variants (e.g., mucinous, micropapillary, metaplastic) exhibit distinct biological and prognostic features. The diagnostic workflow includes standardized steps: sampling, formalin fixation, paraffin embedding, H&E staining, immunohistochemistry (ER, PR, HER2, Ki-67), and molecular testing when needed (FISH, PCR, NGS). Routine biomarkers help define surrogate molecular subtypes (luminal A/B, HER2-positive, triple-negative) and guide systemic therapies. The emergence of the HER2-low category exemplifies how biomarker refinement impacts clinical practice. Additional markers such as PIK3CA and ESR1 mutations, BRCA/HRD status, PD-L1 expression, and tumor-infiltrating lymphocytes (TILs), along with multigene signatures (e.g., Oncotype DX, MammaPrint), further individualize prognostic assessment and treatment selection. Innovative approaches such as liquid biopsy and next-generation sequencing (NGS) enable minimally invasive monitoring and personalized care, especially in advanced disease. Breast cancer pathology is thus a dynamic, integrative discipline central to precision oncology, driven by ongoing technological and molecular advances, and essential to multidisciplinary cancer care.

Mohs micrographic surgery is a surgical technique allowing for nearly 100% histological analysis of the margins of a removed skin tumor, unlike conventional surgery which only analyzes a small portion (around 5-6%). The most common method ("frozen section") involves excising the tumor with minimal margins, spatially orienting the specimen using dyes, then freezing it for sectioning and immediate microscopic analysis by the surgeon themselves. If tumor cells remain at the edges, the surgeon re-operates only the affected area on the same day until clear margins are achieved before reconstruction. A variation, "slow Mohs", uses analysis on paraffin-fixed tissue with a delay. Mohs surgery significantly reduces recurrence rates for carcinomas (basal cell and squamous cell) compared to standard surgery and better preserves healthy tissue. It is recommended by European and American authorities for high-risk skin cancers and is considered mandatory for dermatofibrosarcoma protuberans.

Kaposi's disease is a primarily dermatological disorder characterized histologically by a proliferation of endothelial cells of lymphatic origin, linked to the HHV-8 virus, and occurring most often in a context of reduced immunity, whether linked to age, HIV infection or immunosuppressive therapy. There are 5 epidemiological forms of Kaposi's disease, all of which are predominantly male and of advanced age, especially in the classic form. In the majority of cases, the disease is indolent, but in certain situations, it can become aggressive, either locally or through involvement of internal organs such as the lung and digestive tract. Whenever possible, treatment focuses on restoring immunity. Unfortunately, in some patients this is impossible and/or ineffective, and chemotherapy or, more recently, immunotherapy, is required.

Atypical fibroxanthoma is a rare, malignant skin tumor, mainly affecting elderly, photoexposed men. It accounts for less than 0.2% of skin cancers, and manifests as an erythematous or fleshy nodule, often on the head and neck. Diagnosis is based on anatomopathological analysis, requiring immunostaining to exclude its main differential diagnosis, pleomorphic dermal sarcoma. Extension workup should include ultrasound of lymph node drainage areas. Treatment is based on surgery, with two options: wide excision with 2cm margins, or Mohs micrographic surgery, which reduces recurrence. Recurrences generally occur within the first two years, requiring regular follow-up. Radiotherapy is not recommended. Despite its metastatic potential, appropriate surgical treatment usually ensures a good prognosis.

Adnexal carcinomas are rare cutaneous malignancies arising from the skin's appendages. Skin biopsy is essential for making the diagnosis, and enables the carcinoma to be classified into precise groups and subgroups. Prognosis and initial extension will depend on the histological subtype of the tumor. There is no consensus on the treatment of adnexal carcinomas: large-scale surgery is the standard treatment for localized tumors. Radiotherapy and certain systemic treatments may be proposed for inoperable or metastatic lesions.

Merkel's carcinoma is a rare but highly aggressive cutaneous neuroendocrine tumor whose incidence has increased due to an aging population and increased UV exposure. It is characterized by rapid growth, high risk of recurrence and early metastatic spread. Two subtypes have been identified: Merkel polyomavirus-related (MCPyV), present in 80% of cases in Europe, and UV-related. The main risk factors are advanced age, male gender, light phototypes and immunosuppression. Clinically, it appears as a painless, red or purplish nodule, often on photo-exposed areas. Diagnosis is based on histopathology and immunohistochemistry (CK20+ and synaptophysin+). Extension assessment is essential, and relies on PET-CT, brain MRI and lymph node ultrasound. Staging follows the AJCC 8th edition, distinguishing between localized (I/II), lymph node involved (III) and metastatic (IV) stages. Treatment is based on surgery (excision with 1cm margins) and adjuvant radiotherapy. In the case of lymph node involvement, lymph node dissection and radiotherapy are recommended. Metastatic forms now benefit from immunotherapy (anti-PD-1/PD-L1), which has improved prognosis. Merkel carcinoma has a high recurrence rate (25-50%). Monitoring is based on regular clinical and radiological follow-up over several years. Biomarkers such as NSE and anti-MCPyV serology are currently being evaluated.

Dermatofibrosarcoma (DFSP) is a rare, locally aggressive skin tumour. It appears in the form of indurated plaques or nodules of flesh colour and progressive growth, mainly on the trunk and lower limbs. Diagnosis is based on anatomopathological analysis, with immunostaining to rule out fibrosarcomatous transformation, which occurs in 10-15% of cases. Treatment is based on surgery, with two options: Mohs micrographic surgery when available, to reduce recurrence, or wide excision with 2-3cm margins. In the case of inoperable or metastatic DFSP, imatinib may be proposed. Recurrence occurs with a median delay of 4 to 5 years, justifying regular follow-up.

Since the 2010s, the management of locally advanced and metastatic melanoma has been completely transformed by the use of immune checkpoint inhibitors and anti-BRAF/anti-MEK targeted therapies. These therapies have also recently been used as neoadjuvant and adjuvant treatments in certain high-risk melanoma indications (stage IIB to stage IIID).

Melanoma is a tumor most often found in the skin, developed at the expense of tumor melanocytes. Its incidence doubles every 10 years in France. There are intrinsic and extrinsic risk factors (mainly UV exposure). If a clinical diagnosis is suspected, treatment consists of initial resection without margins, followed by resection of the margins according to the Breslow index. A sentinel lymph node may be included in the revision margin, depending on the Breslow index, the patient's general condition and age. An extension assessment will be carried out depending on the stage of the melanoma operated on.

Cutaneous squamous cell carcinoma (CSC), formerly known as squamous cell carcinoma, is the most common skin cancer after basal cell carcinoma, accounting for 20% of all skin cancers. It is a malignant epithelial tumor of keratinocytic origin. Its incidence has risen sharply in recent decades. CEC is characterized by a more rapid evolution than basal cell carcinoma, with a risk of local recurrence and distant lymphatic and hematogenous metastatic dissemination. Early surgical management usually leads to a cure; adjuvant radiotherapy should be considered in cases of poor prognosis. Finally, immunotherapy has supplanted conventional chemotherapy in the management of advanced forms of the disease, thanks to its superior efficacy (40-50% response rate) and much better tolerability.

Basal cell carcinoma (BCC) is the most common skin tumor, with an incidence varying across Europe, reaching up to 400 cases per 100,000 inhabitants in certain regions. It occurs more frequently in men, with an average age of diagnosis around 70 years. This type of cancer, primarily caused by chronic UV exposure, has a low risk of metastasis (less than 0.05%) but can cause significant local damage. Clinically, BCC presents as erythematous and shiny lesions, with several subtypes: superficial, nodular, and infiltrative. The classification of BCC varies based on its risk of recurrence and treatment complexity, with recommendations regarding surgical margins to be adhered to during excision. The primary treatment is surgical, using conventional or Mohs micrographic techniques depending on the complexity of the tumor. Medical treatments are reserved for low-risk forms or when surgery is not feasible. For advanced BCCs, multidisciplinary discussions are essential to establish the best treatment plan, which may include Sonic Hedgehog pathway inhibitors or radiotherapy for palliative purposes.

Cystic diseases are a group of diseases characterised by the formation of cysts in some organs, particularly the lungs and kidneys, which progressively lead to respiratory or renal failure, requiring organ transplantation in advanced cases. Understanding the mechanisms of these cystic diseases has led to advances in early detection and the development of new treatments to slow their progression to end-stage failure.

We report a rare case of ethmoidal metastasis from a prostatic carcinoma in an elderly patient. This metastasis was revealed solely by exophthalmos, with no associated nasal symptoms. Radiological and histopathological analyses confirmed the unusual diagnosis of a sinus metastasis from a prostatic adenocarcinoma. This case highlights the importance of a thorough diagnostic approach in the presence of an uncommon unilateral orbitopathy.

Molecular analyses performed on cell and tissue samples play a major diagnostic, prognostic, and theragnostic role. Their complexity and diversity, as well as that of the biological matrix involved (formalin-fixed paraffin-embedded tissue, frozen tissue, cytological sample, liquid biopsy), are increasing. The tumor cell content of the sample is an important limiting factor as well as the quality and quantity of nucleic acids extracted from the initial matrix. Therefore, it is crucial to understand and manage the conditions of sample preparation and storage, as those will directly impact the quality of the extracted material and constrain the types of analyses that will be performed. This article highlights the key pre-analytical steps as well as the limitations and interpretative biases that may result from mishandling of the samples.