In medicine, desmoplasia is the growth of fibrous or connective tissue. It is also called desmoplastic reaction to emphasize that it is secondary to an insult. Desmoplasia may occur around a neoplasm, causing dense fibrosis around the tumor, or scar tissue (adhesions) within the abdomen after abdominal surgery.

Desmoplasia is usually only associated with malignant neoplasms, which can evoke a fibrosis response by invading healthy tissue. Invasive ductal carcinomas of the breast often have a scirrhous, stellate appearance caused by desmoplastic formations.

Plasma cell granuloma is a lesional pattern of inflammatory pseudotumour, different from the "inflammatory myofibroblastic tumor" pattern.

It is linked to IgG4-related disease.

Based on a survey of >800, surgical removal of the entire involved kidney plus the peri-renal fat appeared curative for the majority of all types of mesoblastic nephroma; the patient overall survival rate was 94%. Of the 4% of non-survivors, half were due to surgical or chemotherapeutic treatments. Another 4% of these patients suffered relapses, primarily in the local area of surgery rare cases of relapse due to lung or bone metastasis.. About 60% of these recurrent cases had a complete remission following further treatment. Recurrent disease was treated with a second surgery, radiation, and/or chemotherapy that often vincristine and actinomycin treatment. Removal of the entire afflicted kidney plus the peri-renal fat appears critical to avoiding local recurrences. In general, patients who were older than 3 months of age at diagnosis or had the cellular form of the disease, stage III disease, or involvement of renal lymph nodes had a higher recurrence rate. Among patients with these risk factors, only those with lymph node involvement are recommended for further therapy.

It has been suggested that mesoblastic nephroma patients with lymph node involvement or recurrent disease might benefit by adding the ALK inhibitor, crizotinib, or a tyrosine kinase inhibitor, either larotrectinib or entrectinib, to surgical, radiation, and/or chemotherapy treatment regimens. These drugs inhibit NTRK3's tyrosine kinase activity. Crizotinib has proven useful in treating certain cases of acute lymphoblastic leukemia that are associated with the "ETV6-NTRK3" fusion gene while larotrectinib and entrectinib have been useful in treating various cancers (e.g. a metastatic sarcoma, papillary thyroid cancer, non-small-cell lung carcinoma, gastrointestinal stromal tumor, mammary analog secretory carcinoma, and colorectal cancer) that are driven by mutated, overly active tyrosine kinases. Relevant to this issue, a 16-month-old girl with infantile fibrosarcoma harboring the "ETV6–NTRK3" fusion gene was successfully trated with larotrectinib. The success of these drugs, howwever, will likely depend on the relative malignancy-promoting roles of ETV6-NTRK3 protein's tyrosine kinase activity, the lose of ETV6-related transcription activity accompanying formation of ETV6-NTRK3 protein, and the various trisomy chromosomes that populate mesoblastic nephroma.

Guidelines for management of patients up to 18 years with Langerhans cell histiocytosis has been suggested. Treatment is guided by extent of disease. Solitary bone lesion may be amenable through excision or limited radiation, dosage of 5-10 Gys for children, 24-30 Gys for adults. However systemic diseases often require chemotherapy. Use of systemic steroid is common, singly or adjunct to chemotherapy. Local steroid cream is applied to skin lesions. Endocrine deficiency often require lifelong supplement e.g. desmopressin for diabetes insipidus which can be applied as nasal drop. Chemotherapeutic agents such as alkylating agents, antimetabolites, vinca alkaloids either singly or in combination can lead to complete remission in diffuse disease.

The relative risk of breast cancer based on a median follow-up of 8 years, in a case control study of US registered nurses, is 3.7.

Prophylactic mastectomy to reduce the risk of breast cancer is an option.

Some benign tumors need no treatment; others may be removed if they cause problems such as seizures, discomfort or cosmetic concerns. Surgery is usually the most effective approach and is used to treat most benign tumors. In some case other treatments may be of use. Adenomas of the rectum may be treated with sclerotherapy, a treatment in which chemicals are used to shrink blood vessels in order to cut off the blood supply. Most benign tumors do not respond to chemotherapy or radiation therapy, although there are exceptions; benign intercranial tumors are sometimes treated with radiation therapy and chemotherapy under certain circumstances. Radiation can also be used to treat hemangiomas in the rectum. Benign skin tumors are usually surgically resected but other treatments such as cryotherapy, curettage, electrodesiccation, laser therapy, dermabrasion, chemical peels and topical medication are used.

Li–Fraumeni syndrome (LFS) is relatively rare; as of 2011, cases had been reported in more than 500 families. The syndrome was discovered using an epidemiological approach. Li and Fraumeni identified four families in which siblings or cousins of rhabdomyosarcoma patients had a childhood sarcoma, which suggested a familial cancer syndrome. Identification of TP53 as the gene affected by mutation was suggested by the same approach. Over half of the cancers in Li-Fraumeni families had been previously associated with inactivating mutations of the p53 gene and in one primary research study, DNA sequencing in samples taken from five Li–Fraumeni syndrome families showed autosomal dominant inheritance of a mutated TP53 gene.

The standard treatment of COC is enucleation and curettage (E&C). Recurrence following E&C is rare.

Excellent for single-focus disease. With multi-focal disease 60% have a chronic course, 30% achieve remission and mortality is up to 10%.

TS is considered to be a benign dysplasia, although it can be disfiguring and is sometimes itchy. It is not known whether TS lesions have the potential to develop into cancer; while this outcome has never been reported, some polyomaviruses are oncogenic. The natural history of untreated TS is not known and no long-term studies of its progress have been performed. Improvement in immune function has been reported to resolve symptoms in some individual cases. Treatment with antiviral drugs has also been reported to improve symptoms, but only as long as treatment continues.

Definitive treatment for ganglioglioma requires gross total surgical resection, and a good prognosis is generally expected when this is achieved. However, indistinct tumor margins and the desire to preserve normal spinal cord tissue, motor and sensory function may preclude complete resection of tumor. According to a series by Lang et al., reviewing several patients with resected spinal cord ganglioglioma, the 5- and 10-year survival rates after total resection were 89% and 83%, respectively. In that study, patients with spinal cord ganglioglioma had a 3.5-fold higher relative risk of tumor recurrence compared to patients with supratentorial ganglioglioma. It has been recognized that postoperative results correlate closely with preoperative neurological status as well as the ability to achieve complete resection.

With the exception of WHO grade III anaplastic ganglioglioma, radiation therapy is generally regarded to have no role in the treatment of ganglioglioma. In fact, radiation therapy may induce malignant transformation of a recurrent ganglioglioma several years later. Adjuvant chemotherapy is also typically reserved for anaplastic ganglioglioma, but has been used anecdotally in partially resected low grade spinal cord gangliogliomas which show evidence of disease progression.

Desmoplasia originates from the Ancient Greek δεσμός "desmos", "knot", "bond" and πλάσις "plasis", "formation". It is usually used in the description of desmoplastic small round cell tumors.

Neoplasia is the medical term used for both benign and malignant tumors, and is used as a blanket term that refers to abnormal, excessive, uncoordinated, and autonomous cellular/tissue growth.

Desmoplasia refers to growth of dense connective tissue or stroma. This growth is characterized by low cellularity with hyalinized or sclerotic stroma and disorganized blood vessel infiltration. This growth is called a desmoplastic response and occurs as result of injury or neoplasia. This response is coupled with malignancy in non-cutaneous neoplasias, and with benign or malignant tumors if associated with cutaneous pathologies.

The heterogeneity of tumor cancer cells and stroma cells combined with the complexities of surrounding connective tissue suggest that understanding cancer by tumor cell genomic analysis is not sufficient; analyzing the cells together with the surrounding stromal tissue may provide more comprehensive and meaningful data.

Carcinogenesis, also called oncogenesis or tumorigenesis, is the formation of a cancer, whereby normal cells are transformed into cancer cells. The process is characterized by changes at the cellular, genetic, and epigenetic levels and abnormal cell division. Cell division is a physiological process that occurs in almost all tissues and under a variety of circumstances. Normally the balance between proliferation and programmed cell death, in the form of apoptosis, is maintained to ensure the integrity of tissues and organs. According to the prevailing accepted theory of carcinogenesis, the somatic mutation theory, mutations in DNA and epimutations that lead to cancer disrupt these orderly processes by disrupting the programming regulating the processes, upsetting the normal balance between proliferation and cell death. This results in uncontrolled cell division and the evolution of those cells by natural selection in the body. Only certain mutations lead to cancer whereas the majority of mutations do not.

Variants of inherited genes may predispose individuals to cancer. In addition, environmental factors such as carcinogens and radiation cause mutations that may contribute to the development of cancer. Finally random mistakes in normal DNA replication may result in cancer causing mutations. A series of several mutations to certain classes of genes is usually required before a normal cell will transform into a cancer cell. On average, for example, 15 "driver mutations" and 60 "passenger" mutations are found in colon cancers. Mutations in genes that regulate cell division, apoptosis (cell death), and DNA repair may result in uncontrolled cell proliferation and cancer.

Cancer is fundamentally a disease of regulation of tissue growth. In order for a normal cell to transform into a cancer cell, genes that regulate cell growth and differentiation must be altered. Genetic and epigenetic changes can occur at many levels, from gain or loss of entire chromosomes, to a mutation affecting a single DNA nucleotide, or to silencing or activating a microRNA that controls expression of 100 to 500 genes. There are two broad categories of genes that are affected by these changes. Oncogenes may be normal genes that are expressed at inappropriately high levels, or altered genes that have novel properties. In either case, expression of these genes promotes the malignant phenotype of cancer cells. Tumor suppressor genes are genes that inhibit cell division, survival, or other properties of cancer cells. Tumor suppressor genes are often disabled by cancer-promoting genetic changes. Finally Oncovirinae, viruses that contain an oncogene, are categorized as oncogenic because they trigger the growth of tumorous tissues in the host. This process is also referred to as viral transformation.

The standard initial treatment is to remove as much of the tumor as possible without worsening neurologic deficits. Radiation therapy has been shown to prolong survival and is a standard component of treatment. There is no proven benefit to adjuvant chemotherapy or supplementing other treatments for this kind of tumor. Although temozolomide is effective for treating recurrent anaplastic astrocytoma, its role as an adjuvant to radiation therapy has not been fully tested.

Quality of life after treatment depends heavily on the area of the brain that housed the tumor. In many cases, patients with anaplastic astrocytoma may experience various types of paralysis, speech impediments, difficulties planning and skewed sensory perception. Most cases of paralysis and speech difficulties can be rehabilitated with speech, occupational, physical, and vision therapy.

TS was first described in a 1995 case report as "ciclosporin-induced folliculodystrophy", thought at the time to be an adverse effect of ciclosporin treatment. A subsequent report in 1999, which introduced the term "trichodysplasia spinulosa", used electron microscopy to identify the presence of virus particles in affected cells consistent with what were at the time known as papovaviruses. (The group has since been divided into the papillomavirus and polyomavirus families.) In 2010, researchers used rolling circle amplification to recover viral DNA from TS lesions and thus discovered a novel polyomavirus, trichodysplasia spinulosa polyomavirus (TSPyV). There is compelling evidence that TSPyV is the direct causative agent of TS.

Surgical resection of the tumor with wide margins remains the preferred method of treatment, and has shown the most success against the disease. Recently, limb-sparing surgery has been explored with moderate success.

In cases of advanced, recurrent, or metastasized disease, or if the tumor is inoperable, chemotherapy and radiation are the standard of care, although the overall success rates with these remains low.

No curative treatment against EV has been found yet. Several treatments have been suggested, and acitretin 0.5–1 mg/day for 6 months’ duration is the most effective treatment owing to antiproliferative and differentiation-inducing effects.

Interferons can also be used effectively together with retinoids.

Cimetidine was reported to be effective because of its depressing mitogen-induced lymphocyte proliferation and regulatory T cell activity features. A report by Oliveira "et al." showed that cimetidine was ineffective. Hayashi "et al." applied topical calcipotriol to a patient with a successful result.

As mentioned, various treatment methods are offered against EV; however, most importantly, education of the patient, early diagnosis, and excision of the tumoral lesions take preference to prevent the development of cutaneous tumors.

ADH, if found on a surgical (excisional) biopsy of a mammographic abnormality, does not require any further treatment, only mammographic follow-up.

If ADH is found on a core (needle) biopsy (a procedure which generally does not excise a suspicious mammographic abnormality), a surgical biopsy, i.e. a breast lumpectomy, to completely excise the abnormality and exclude breast cancer is the typical recommendation.

The age-standardized 5-year relative survival rate is 23.6%. Patients with this tumor are 46 times more likely to die than matched members of the general population. It is important to note that prognosis across age groups is different especially during the first three years post-diagnosis. When the elderly population is compared with young adults, the excess hazard ratio (a hazard ratio that is corrected for differences in mortality across age groups) decreases from 10.15 to 1.85 at 1 to 3 years, meaning that the elderly population are much more likely to die in the first year post-diagnosis when compared to young adults (aged 15 to 40), but after three years, this difference is reduced markedly.

Typical median survival for anaplastic astrocytoma is 2–3 years. Secondary progression to glioblastoma multiforme is common. Radiation, younger age, female sex, treatment after 2000, and surgery were associated with improved survival in AA patients.

Epithelioid sarcoma (especially advanced stage, recurrent, or metastasized disease) has been shown to be resistant to traditional cancer therapies, necessitating further exploration of novel treatment methods and techniques. Because of the relatively poor response of epithelioid sarcoma to traditional cancer treatments (surgery, chemotherapy, and radiation), new treatment strategies are being looked to.

The calcifying odotogenic cyst or the Gorlin cyst, now known in the WHO Classification of Tumours as the calcifying cystic odontogenic tumor, is a benign odontogenic tumor of cystic type most likely to affect the anterior areas of the jaws. It is most common in people in their second to third decades but can be seen at almost any age. On radiographs, the calcifying odontogenic cyst appears as a unilocular radiolucency (dark area). In one-third of cases, an impacted tooth is involved. Microscopically, there are many cells that are described as "ghost cells", enlarged eosinophilic epithelial cells without nuclei.

Most fibroadenomas are simply monitored. Some are treated by surgical excision. They are removed with a small margin of normal breast tissue if the preoperative clinical investigations are suggestive of the necessity of this procedure. A small amount of normal tissue must be removed in case the lesion turns out to be a phyllodes tumour on microscopic examination.

Because needle biopsy is often a reliable diagnostic investigation, some doctors may decide not to operate to remove the lesion, and instead opt for clinical follow-up to observe the lesion over time using clinical examination and mammography to determine the rate of growth, if any, of the lesion. A growth rate of less than sixteen percent per month in women under fifty years of age, and a growth rate of less than thirteen percent per month in women over fifty years of age have been published as safe growth rates for continued non-operative treatment and clinical observation.

Some fibroadenomas respond to treatment with ormeloxifene.

Fibroadenomas have not been shown to recur following complete excision or transform into phyllodes tumours following partial or incomplete excision.

Ganglioglioma is a rare, slow-growing primary central nervous system (CNS) tumor which most frequently occurs in the temporal lobes of children and young adults.

Prostatic stromal tumour of uncertain malignant potential, abbreviated PSTUMP, is a rare tumour of the prostate gland stroma that may behave benign or like cancer, i.e. "malignant".

It can be abbreviated STUMP; an abbreviation used for a uterine lesion of uncertain malignant potential.

It is also known as prostatic stromal proliferation of uncertain malignant potential (abbreviated PSPUMP).