Urothelial tumor classification

1. Gastroepato
2. Oncology
3. Urothelial tumor classification
4. Bladder cancer
5. Kidney tumor

Epithelial bladder tumors

They constitute 3.2% of all neoplasms and represent the seventh seat in order of frequency in our organism: in the world 2.6 x 10⁵ new cases are calculated per year in the male population and 7.5 X 10⁴ in the female one. The prevalence of male gender in urothelial carcinomas is net, while the male / female ratio approaches 1: 1 in squamous epithelium carcinomas and in adenocarcinomas.
The tumors of the pelvis and ureter are rare and make up only 2.5% of the tumors of the urinary tract. Overall, bladder tumors are much more common in industrialized nations (Europe, USA, Australia) than in third countries.
In relation to the histotype, marked differences in frequency are observed by geographical area: urothelial neoplasms are very common in the western world (85% of the total), while squamous epithelium carcinomas represent more than half of those affecting the African populations, due to the prevalence of schistosomiasis and the corresponding chronic cystitis with squamous metaplasia. Adenocarcinomas are very rare everywhere.

WHO classification of urothelial tumors

Non-invasive urothelial neoplasms

Urothelial papilloma
Inverted urothelial papilloma
Non-invasive papillary urothelial neoplasm of low malignant potential
Non-invasive papillary urothelial carcinoma, low grade
Non-invasive papillary urothelial carcinoma, high grade
Urothelial carcinoma in situ

Infiltrating urothelial carcinoma

with squamous differentiation
with glandular differentiation
with trophoblastic differentiation
at nests
microcystic
micropapillary
imitation lymphoepithelioma
-like lymphoma
plasmacytoid
sarcomatoid
or giant cells
undifferentiated

Squamous neoplasms

Squamous cell papilloma
Warty carcinoma
Squamous cell carcinoma

Glandular neoplasms

villous adenoma
Adenocarcinoma
- enteric
- mucinous
- ring-shaped cells with a setting
- clear cellAltri tipi neoplastici
Neuroendocrine tumors
• Paraganglioma
• Carcinoid
• Small cell carcinoma
Melanocytic tumors
• Nevo
• Melanoma
Mesenchymal tumors
• Hemangioma
• Leiomyoma
• Malignant fibrous histiocytoma
• Osteosarcoma
• Angiosacoma
• Leiomyosarcoma
• Rhabdomyosarcoma
Lymphoid and hematopoietic tumors
• Lymphoma
• Plasmacytoma

General morphological aspects

The macroscopic appearance of the bladder neoplasms can basically coexist:
• a normal or mild erythema and opacification of the mucosa (which corresponds to the so-called flat mucosa carcinoma);
• single or multiple exophytic lesions, with a thin and ramified structure, now squat and coarse that protrude into the lumen, and correspond to the most non-invasive papillary neoplasms. The most common localization is at the trigone, near the ureteral outlets, the lateral and posterior walls.
The vegetations can be expanded on most of the surface, occupying extensively the lumen.

A peculiar esophagic appearance with a cupoliform attitude, and with a smooth mucous lining, is observed in the case from the inverted papioloma;
• solid lesions, with plaque detected and with fringed and irregular edges, which correspond to infiltrating neoplasms.
The neoplastic tissue is necrotic, friable, extensively ulcerated in surfaces, sometimes covered with blood clots. The wall may appear lardacea, rigid and thickened. The prevalent localization is at the base of the bladder, with the exception of adenocarcinoma of uracal origin which is localized at a time. Obstructive complications result from the involvement of ureteral orifices and of the urethra

Benign epithelial neoplasms

The histological classification is complex and articulated, without explicit distinction between benign and malignant forms. However, the two variants of papioloma must be considered benign: esophagic and inverted:
• in the first, the slender vegetations raised on the surface are formed by vascularized stromal shoots covered by urothelium devoid of cytological atypia;
• in the second, the surface is covered by thin or even atrophic urothelium and the proliferation of typical epithelial cells, collected in anastomosed cords, delimited by the m.b., develops in the own tunic without reaching the detrusor muscle bundles

Malignant epithelial neoplasms

They are distinguished in non-invasive and infiltrating. You stressed that the containment of the neoplasia in the thickness of the epithelium without exceeding the m.b. (which in other organs is defined as carcinoma in situ receives in the bladder two distinct definitions in relation to the endoscopic aspect: of non-invasive carcinoma of papillary lesions and of in situ carcinoma proper when present on flat mucosa.
Non-invasive papillary lesions of increasing malignancy are represented by papillary urothelial neoplasia with low potential for malignancy, low grade urothelial carcinoma and high grade urothelial carcinoma.
The distinctive elements, and indicators of growing malignancy, are:
• alterations of the general architecture of the epithelium (loss of polarity and of superficial umbrella cells);
• increase in thickness of the epithelium and progressive fusion of the papillae;
• cytological irregularities, such as volume and nuclear polymorphism, characters of chromatin, presence and volume of nucleoli;
• number and location (basal or superficial) of mitosis.
Three degrees (G 1 - G 3) of progressive gravity are then identified. The same cytological grading also applies to infiltrating urothelial tumors, which can n even occur with modest anomalies (G 1), but mostly demonstrate severe atypias (G 2 - 3). In situ carcinoma cytological malignancy is always high.
In infiltrating forms, in addition to pure urothelial carcinoma, histological variants (squamous, glandular, nests, microcyst, micropapillary, sarcomatoid, giant cells and spindles, lymphoepithelioma-like) defined by the presence, next to the atypical urothelium, of peculiar that justify the definition of variety, but not a separate taxonomic location. The distinction of a separate histotype (squamous cell carcinoma and adenocarcinoma) is accepted only when the neoplasm is formed exclusively by pavement cells, often keratinizing, or by ghiandolariformi structures. Adenocarcinoma is divided into two forms, one of an intestinal type, linked to the presence of a long-term intestinal metaplasia, the other of uracal origin.
The neoplastic infiltration progressively extends, starting from the subepithelial connective tissue to the detrusor muscle and then to the pervesical fat, to then involve nearby organs, the pelvic and abdominal walls.
The evaluation of the extent of the infiltrative process is possible only with the examination of the surgical material of the bladder exeresis which, associated with the examination of the locoregional lymph nodes and the presence of distant metastases, allows the pathological staging of the disease

Grading bladder tumors

T Primitive tumor
T x The presence of the tumor can not be defined
TO No evidence of neoplasia
Ta Non-invasive papillary carcinoma
Tis Carcinoma in situ on a flat mucosa
T1 Tumor that invades the subepithelial connective tissue
T 2 Tumor that invades the muscle
T 2 a Tumor that invades the inner half of the muscular tunic
T 2 b Tumor that invades the outer half of the muscular tunic
T 3 Tumor that invades the periviscical tissues
T 3 a Microscopic identification of the neoplastic invasion
T 3 b Macroscopic identification of the neoplastic invasion (extravescical mass)
T4 Invading tumor: prostate, uterus, vagina, pelvic or abdominal wall
T 4 to Tumor invading prostate, uterus, vagina
T4b Tumor invading pelvic or abdominal wall
N Lymph nodes
N x The lymph node status can not be defined
NO Absent lymph nodes
N1 Metastasis in a lymph node of size up to 2 cm
N2Metastasis in one or more lymph nodes smaller than 5 cm
N3 Metastasis in a lymph node larger than 5 cm
M Metastasis a
Mx The presence of metastases can not be defined
MO Metastases absent
MI Metastases present
 

Tumor index