Subtypes of fibromatosis include -

- Juvenile fibromatosis

- Fibromatosis colli: Non-neoplastic sternocleidomastoid muscle enlargement in early infancy. Does not generally require resection and responds well to physiotherapy.

- Infantile digital fibromatosis

- Infantile myofibromatosis

- Ipofibromatosis

- Fibromatosis hyalinica multiplex

- Plantar fibromatosis

- Penile fibromatosis (Peyronie's disease)

- Palmar fibromatosis (Dupuytren's contracture)

Vascular tissue neoplasms, like neoplasms of all tissues, are classified to benign and malignant ones, according to their biological behavior.

Hemangiopericytoma located in the cerebral cavity is an aggressive tumor of the Mesenchyme with oval nuclei with scant cytoplasm. "There is dense intercellular reticulin staining. Tumor cells can be fibroblastic, myxoid, or pericytic. These tumors, in contrast to meningiomas, do not stain with epithelial membrane antigen. They have a grade 2 or 3 biological behavior, and need to be distinguished from benign meningiomas because of their high rate of recurrence (68.2%) and metastases (Maier et al. 1992; Kleihues et al. 1993 )."

A vascular tissue neoplasm is a tumor arising from endothelial cells, the cells that line the wall of blood vessels and lymphatic vessels, as well as the heart. Vascular tissue neoplasms is a group containing tumors with the same tissue origin; in other words, it denotes histological classification, rather than anatomic (i.e. where in the body the neoplasm is found) or clinical one. They can occur everywhere in the body where vessels are to be found.

Other names include "musculoaponeurotic fibromatosis," referring to the tendency of these tumors to be adjacent to and infiltrating deep skeletal muscle, aggressive fibromatosis and "desmoid tumor." A clear difference should be made between intra-abdominal and extra-abdominal localizations. Fibromatosis is a different entity from neurofibromatosis.

A hemangiopericytoma (HPC) is a type of soft tissue sarcoma that originates in the pericytes in the walls of capillaries. When inside the nervous system, although not strictly a meningioma tumor, it is a meningeal tumor with a special aggressive behavior. It was first characterized in 1942.

By hypersecretion of renin, JCT causes hypertension, often severe and usually sustained but occasionally paroxysmal, and secondary hyperaldosteronism inducing hypokalemia, though the later can be mild despite high renin. Both of these conditions may be corrected by surgical removal of the tumor. Asymptomatic cases have been reported.

Infantile hemangiopericytoma (also known as "Congenital hemangiopericytoma") is a cutaneous condition characterized by single or multiple dermal and subcutaneous nodules that may be alarmingly large at birth or grow rapidly.

JCT is morphologically characterized by multiple foci malignant mesenchymal epithelioid cells with, often with admixed necrosis, and a perivascular growth pattern. The immunophenotype is rather characteristic, as the neoplastic cells express renin, CD34, smooth muscle actin, CD138, vimentin, collagen IV and is negative for cytokeratins as well as for S100, c-Kit and desmin.

Infantile myofibromatosis (also known as "Congenital generalized fibromatosis," and "Congenital multicentric fibromatosis") is the most common fibrous tumor of infancy, in which eighty percent of patients have solitary lesions with half of these occurring on the head and neck, and 60% are present at or soon after birth. Less commonly, infantile myofibromatosis presents as multiple lesions of skin, muscle, and bone with about 1/3 of these cases also having lesions in their visceral organs. All of these cases have an excellent prognosis with their tumors sometimes regressing spontaneously except for those cases in which there is visceral involvement where the prognosis is poor. Infantile myofibromatosis and the classic form of mesoblastic nephroma have been suggested to be the same disease because of their very similar histology. However, studies on the distribution of cell-type markers (i.e. cyclin D1 and Beta-catenin) indicate that the two neoplasms likely have different cellular origins.

Aggressive infantile fibromatosis is a locally recurring, non-metastasizing lesion, presenting with a single or multiple fast-growing masses that are present at birth or occur within the first year of life.

Infantile digital fibromatosis (also known as an "Inclusion body fibromatosis," "Infantile digital myofibroblastoma," and "Reye tumor") usually occurs as a small, asymptomatic, nodular, dermal fibrous proliferation at the extensor or lateral surface of a finger or toe.

Individuals presenting with fibrosarcoma are usually adults aged thirty to fifty five years, often presenting with pain. In adults, males have a higher incidence for fibrosarcoma than females.

Fibrosarcoma (fibroblastic sarcoma) is a malignant mesenchymal tumour derived from fibrous connective tissue and characterized by the presence of immature proliferating fibroblasts or undifferentiated anaplastic spindle cells in a storiform pattern. It is usually found in males aged 30 to 40 . It originates in fibrous tissues of the bone and invades long or flat bones such as femur, tibia, and mandible. It also involves periosteum and overlying muscle.

Congenital mesoblastic nephroma typically (76% of cases) presents as an abdominal mass which is detected prenatally (16% of cases) by ultrasound or by clinical inspection (84% of cases) either at birth or by 3.8 years of age (median age ~1 month). The neoplasm shows a slight male preference. Concurrent findings include hypertension (19% of cases), polyhydramnios (i.e. excess of amniotic fluid in the amniotic sac) (15%), hematuria (11%), hypercalcemia (4%), and elevated serum levels of the kidney-secreted, hypertension-inducing enzyme, renin (1%). Congenital anomalies have been reported in 11 patients: 6 with genitourinary anomalies, 2 with gastrointestinal anomalies, 1 with hydrocephalus, and 1 with the Beckwith–Wiedemann syndrome. The vast majority of patients present with localized (i.e. non-metastatic) disease. Most patients' disease is classified at presentation as stage I or II (i.e. localized), few patients present with stage III (i.e. locally advanced/infiltrating), and virtually no patients present with stage IV (metastases present or V (i.e. tumors in both kidneys) disease (see staging of renal cancer).

Congenital mesoblastic nephroma, while rare, is the most common kidney neoplasm diagnosed in the first three months of life and accounts for 3-5% of all childhood renal neoplasms. This neoplasm is generally non-aggressive and amenable to surgical removal. However, a readily identifiable subset of these kidney tumors has a more malignant potential and is capable of causing life-threatening metastases. Congenital mesoblastic nephroma was first named as such in 1967 but was recognized decades before this as fetal renal hamartoma or leiomyomatous renal hamartoma.

An affected infant typically has the following triad of signs and symptoms: soft-tissue swelling, bone lesions, and irritability. The swelling occurs suddenly, is deep, firm, and may be tender. Lesions are often asymmetric and may affect several parts of the body. Affected bones have included the mandible, tibia, ulna, clavicle, scapula, ribs, humerus, femur, fibula, skull, ilium, and metatarsals. When the mandible (lower jaw bone) is affected, infants may refuse to eat, leading to failure to thrive.

Infantile systemic hyalinosis or juvenile systemic hyalinosis is an allelic autosomal-recessive condition characterized by multiple skin nodules, hyaline deposition, gingival hypertrophy, osteolytic bone lesions, and joint contractures.

Diffuse infantile fibromatosis is a condition affecting infants during the first 3 years of life. It is usually confined to the muscles of the arms, neck, and shoulder area. There is a multicentric infiltration of muscle fibers with fibroblasts resembling those seen in aponeurotic fibromas.

Infantile cortical hyperostosis is a self-limited inflammatory disorder of infants that causes bone changes, soft tissue swelling and irritability. The disease may be present at birth or occur shortly thereafter. The cause is unknown. Both familial and sporadic forms occur. It is also known as Caffey disease or Caffey's disease.

Infantile acne is a cutaneous condition that presents at 3 to 6 months of age.

Malignant infantile osteopetrosis, also known as infantile autosomal recessive osteopetrosis or simply infantile osteopetrosis is a rare osteosclerosing type of skeletal dysplasia that typically presents in infancy and is characterized by a unique radiographic appearance of generalized hyperostosis - excessive growth of bone.

The generalized increase in bone density has a special predilection to involve the medullary portion with relative sparing of the cortices. Obliteration of bone marrow spaces and subsequent depression of the cellular function can result in serious hematologic complications. Optic atrophy and cranial nerve damage secondary to bony expansion can result in marked morbidity. The prognosis is extremely poor in untreated cases. Plain radiography provides the key information to the diagnosis. Clinical and radiologic correlations are also fundamental to the diagnostic process, with additional gene testing being confirmatory.

Hematologic manifestations related to bone marrow suppression and subsequent pancytopenia are a major source of morbidity and mortality. Additionally extramedullary hematopoiesis can result in liver and spleen dysfunction. Cranial nerve dysfunction and neurologic complications are usually associated with infantile osteopetrosis. Expansion of the skull bone leads to macrocephaly. Additionally, linear growth retardation that is not apparent at birth, delayed motor milestones and poor dentition can occur.

Adult patients have worsening myalgias, bone pains and fatigue which are followed by recurrent fractures. Children present with difficulty in walking, stunted growth and deformities of the skeleton (features of rickets).

Many conditions affect the human integumentary system—the organ system covering the entire surface of the body and composed of skin, hair, nails, and related muscle and glands. The major function of this system is as a barrier against the external environment. The skin weighs an average of four kilograms, covers an area of two square meters, and is made of three distinct layers: the epidermis, dermis, and subcutaneous tissue. The two main types of human skin are: glabrous skin, the hairless skin on the palms and soles (also referred to as the "palmoplantar" surfaces), and hair-bearing skin. Within the latter type, the hairs occur in structures called pilosebaceous units, each with hair follicle, sebaceous gland, and associated arrector pili muscle. In the embryo, the epidermis, hair, and glands form from the ectoderm, which is chemically influenced by the underlying mesoderm that forms the dermis and subcutaneous tissues.

The epidermis is the most superficial layer of skin, a squamous epithelium with several strata: the stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum basale. Nourishment is provided to these layers by diffusion from the dermis, since the epidermis is without direct blood supply. The epidermis contains four cell types: keratinocytes, melanocytes, Langerhans cells, and Merkel cells. Of these, keratinocytes are the major component, constituting roughly 95 percent of the epidermis. This stratified squamous epithelium is maintained by cell division within the stratum basale, in which differentiating cells slowly displace outwards through the stratum spinosum to the stratum corneum, where cells are continually shed from the surface. In normal skin, the rate of production equals the rate of loss; about two weeks are needed for a cell to migrate from the basal cell layer to the top of the granular cell layer, and an additional two weeks to cross the stratum corneum.

The dermis is the layer of skin between the epidermis and subcutaneous tissue, and comprises two sections, the papillary dermis and the reticular dermis. The superficial papillary dermis with the overlying rete ridges of the epidermis, between which the two layers interact through the basement membrane zone. Structural components of the dermis are collagen, elastic fibers, and ground substance. Within these components are the pilosebaceous units, arrector pili muscles, and the eccrine and apocrine glands. The dermis contains two vascular networks that run parallel to the skin surface—one superficial and one deep plexus—which are connected by vertical communicating vessels. The function of blood vessels within the dermis is fourfold: to supply nutrition, to regulate temperature, to modulate inflammation, and to participate in wound healing.

The subcutaneous tissue is a layer of fat between the dermis and underlying fascia. This tissue may be further divided into two components, the actual fatty layer, or panniculus adiposus, and a deeper vestigial layer of muscle, the panniculus carnosus. The main cellular component of this tissue is the adipocyte, or fat cell. The structure of this tissue is composed of septal (i.e. linear strands) and lobular compartments, which differ in microscopic appearance. Functionally, the subcutaneous fat insulates the body, absorbs trauma, and serves as a reserve energy source.

Conditions of the human integumentary system constitute a broad spectrum of diseases, also known as dermatoses, as well as many nonpathologic states (like, in certain circumstances, melanonychia and racquet nails). While only a small number of skin diseases account for most visits to the physician, thousands of skin conditions have been described. Classification of these conditions often presents many nosological challenges, since underlying etiologies and pathogenetics are often not known. Therefore, most current textbooks present a classification based on location (for example, conditions of the mucous membrane), morphology (chronic blistering conditions), etiology (skin conditions resulting from physical factors), and so on. Clinically, the diagnosis of any particular skin condition is made by gathering pertinent information regarding the presenting skin lesion(s), including the location (such as arms, head, legs), symptoms (pruritus, pain), duration (acute or chronic), arrangement (solitary, generalized, annular, linear), morphology (macules, papules, vesicles), and color (red, blue, brown, black, white, yellow). Diagnosis of many conditions often also requires a skin biopsy which yields histologic information that can be correlated with the clinical presentation and any laboratory data.