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Cryptorchidism

Congenital defect; testis fails to decent in scrotum
Can be unilateral or bilateral in nature
Grossly:

A cryptorchid testis remains small at puberty, probably because of its higher than optimal temperature.
Softer in consistency
Sterile in function
Superimposed atropy after puberty and testes becomes small and fibrotic

Microscopically:

Spermatogenesis is absent
the interstitial cells are present and active

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Focal Sertoli cell hyperplasia in the cryptorchid testis of a ram.

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Cryptochid Testies

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Hypoplasia of testies

Failure of testies to develop fully
A congenital abnormalities
It is usually suspected at the time of puberty when animal exhibit absence of fertility.

Grossly:

Affected testies is smaller than normal

Microscopically:

Hyalinization of basement membrane
Reduction in diameter of seminiferous tubules.
No spermatogenesis

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_{Figure: Testicular hypoplasia in a cat.}

Seminiferous tubules contain only Sertoli cells and a few germ cells. There is some degeneration of Sertoli cells with vacuolation.

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Degeneration and Atropy of testies

Etiology:

Heat
Trauma
Infection

Grossly:

Testies become soft and flabby
Reduction in size of testies (with out ongoing loss of fluid and reduction in germinal epithelium relative to the stroma) and firm consistency
lacks turgor
Cut surface doesn’t bulges as it does in normal testies
Wrinkling of testicular capsule
Testies appear darker in color

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31/05/2021

Figure: Unilateral testicular atrophy in a ram. The epididymis of the atrophic testis appears disproportionately large.

Microscopic

Reduction of spermatogenesis, shrinking of tubular diameter, reduction in the number of sertoli cells, reduction in interstitial endocrine cell size and a wavy and thickened hyaline basement membrane.
Progressive fibrosis in later stages.

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Fig: Early stages of testicular degeneration in a dog.Multinucleated spermatids are within the lumen.

_{Figure: Testicular degeneration in a dog}.

Tubules are at various stages of degeneration including a Sertoli cell only pattern, reduced spermatogenesis, and buckling of basement membranes, hyalinized tubules, and depletion of both germinal and Sertoli cells. Prominent and hyalinized blood vessels are in the interstitium.

Figure: Advanced testicular degeneration with spermatogenic arrest in the seminiferous tubule of a dog.

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Orchitis

It’s an inflammation of testies
True orchitis (inflammation of the testis) is much less common than epididymitis,

Etiology:

Brucellosis
Campylobacterium
Corynebacterium spss
Actinomyces etc.

Gross:

Edema and swelling of affected testies
Accumulation of serous fluid in scrotum
In chronic case fibrosis and atropy

Microscopic:

Interstitial edema
Infiltration of mononuclear cells
During healing there is varying degree of fibrosis.

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Necrotizing Orchitis-

Gray-brown, initially soft and later firm, necrotic debris replaces an irregular but large portion of the testis.

Granulomatous Orchitis-

There is granulomatous inflammation surrounding aggregates of spermatozoa and mineral that replaced the seminiferous tubules after they were destroyed.
Lymphocytes and plasma cells predominate in the surrounding interstitium.

Intratubular orchitis –

appears grossly as poorly defined, up to 1-cm yellow foci that become firm and white as the lesions become older.
Initially, the affected tubules have acute inflammatory debries
The lining of the tubules is lost, but the tubular outlines remain.
Spermatic granulomas frequently form. In the center of these granulomas, spermatozoa are within macrophages or free within the tissue. Macrophages and lymphocytes surround the spermatozoa and with time, collagen is formed at the edge of the lesion.

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Epididymitis

Its an inflammation of epididymis

Etiology:

Brucella sps.

Macroscopic

Epididimis is enlarged and there is accumulation of purulent/mucous exudates in scrotum
In chronic case there is fibrosis and atropy of epididymis.

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Sperm Granuloma

Develops when sperm escape from the duct system

Etiology:

May be due to infection (Brucella) or
may be sequel to cystic dilatation of epididymal duct that ruptures.

Microscopically:

Closely resembles with tubercules
Sperm body is markedly resistant to disintegration and therefore inspissated sperm can be found in granuloma

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31/05/2021

Example:

Obstruction of duct > Cystic dilation of duct >Duct become impacted and inspissated with sperm > Rupture of duct > Release of sperm > sperm body is markedly resistant to disintegration > Sperm granuloma.

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Funiculitis: Inflammation of spermatic cord�

Prostatitis: Inflammation of prostrate gland.

Etiology:

harmonal imbalance
Pyogenic bacteria e.g streptococcus, staphylococcus

Gross finding:

Enlargement of prostrate
Obstruction of rectal passage
Hematuria

Microscopic findings:

Infiltration of neutrophil and liquifactive necrosis
Chronic inflammation there is hyperplasia of glandular epithelium, fibroblast and smooth muscle fibres
Cystic glandular hyperplasia
Infiltration of lymphocytes

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HYPERPLASIA OF THE PROSTATE:�

Prostatic hyperplasia very common in dogs and is testosterone dependent. Also occur in bull.
it usually becomes evident at 4 to 5 years of age and increases in severity with advancing years.
Hyperplasia does not occur in castrated dogs, and castration causes a reduction in size

Etiology:

Apparently, hormonal imbalances (higher estrogen: testosterone ratio) play an important role in the development of prostatic hyperplasia
Prolactin may also be involved.

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HYPERPLASIA OF THE PROSTATE:�

Grossly

The hyperplastic gland is larger than normal,
Surface is either smooth and regular or irregularly nodular
Fluctuating cysts and venous an lymphatic ectasias may be present beneath the capsule.

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31/05/2021

Figure: Prostatic hyperplasia in a dog with almost symmetrical enlargement of the prostate gland.

Microscopically

the condition is characterized by hyperplasia of glandular and stromal elements with cyst formation.

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Balanophosthitis

Balanitis (inflammation of the glans, the rounded head of the penis) and posthitis (inflammation of the foreskin)
Usually occur together as balanoposthitis: inflammation of both the glans and foreskin.
Occurs more frequently castrated male.

Etiology:

Infectious Example: Trichomonas fetus, BHV-1 virus, Vesicular exanthema virus, Actinomyces sps.
Injuries,
Phimosis
Tumors
Urolithiasis

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Etio-pathogenesis

Alteration to structure because of lack of testosterone and/or normal development and the tendency of these animals to urinate within their prepuce.
Retention of urine in the preputial cavity irritates and damages the mucous membrane and creates an environment for the overgrowth of bacteria
Urease produce by bacteria split urea to ammonia, a toxic molecule that further damages the preputial epithelium, causing erosion and ulceration.
Non specific posthitis occurs in all species but is most common in the gilts. In gilts, it is believed to occur because of lack of extrusion of the penis with a resultant build up of waxy smegma and bacterial over growth..

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Macroscopic findings:�

Hyperemia, swelling, vesicles, pustules, and 1- to 2-mm ulcers, especially on mucosal surface of penis and prepuce.
Thin purulent preputial discharge
Development of lymphoid nodules, especially over the base of the penis and preputial reflection.
In more severe form edema, abscessation, and even myiasis.
Deformity of the preputial orifice and phimosis may occur following healing of ulcers.

Dr. Bikash Puri

31/05/2021

Figure: Phaloposthitis, Bovine Herpesvirus 1, Penis (Free Part), Bull. Note the vesicles and pustules of the mucosa.. Intranuclear inclusion bodies are present microscopically, briefly in epithelial cells of the penis and prepuce during the vesiculopustular stage.

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Microscopic �

Histologic appearance of lesions is nonspecific, with superficial necrosis, reactive epithelial hyperplasia, and underlying granulation tissue.
Foci of dead cells within the epithelium and spongiosis.
Intranuclear inclusion bodies may appear in epithelial cells.
Dead cells slough and shallow ulcers form.
Lymphocytic infiltration: neutrophils migrate into the affected epithelium and lymphocytes appear in the submucosa.

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Neoplasm of testies

Neoplasm of testies are common in older dogs but rare in other species.
Usually arise from germ cells, interstitial endocrine cells or sertoli cells
Occasionally neoplasm of testicular mesenchymal tissues or metastatic neoplasm are found
Three common primary neoplasm are-

Seminoma
Interstitial cell tumor
Serotoli cell tumor

Primary neoplasm are almost always benign
Metastasis when occur, is identified by nodules in the spermatic cord, scrotal lymph node or beyond.

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Germ Cell Neoplasm

Semioma-

Most common testicular neoplasm in the aged stallion and 2^nd most common testicular neoplasm in canine.
More prevalent in cryptorchid testes
Multicentric origin within testis and local invasiveness are characteristic
Metastasis is rare.
Grossly:

Neoplasm is homogenous, white or ping gray and firm
Bulges when cut and have fine fibrous trabeculae.

Microscopically:

Seminomas are either intratubular or diffuse
Neoplastic cells are large round cells with scant cytoplasm
Nucleous is large and have prominent nucleolus
Anisokaryosis is upto sixfold but most cells are large and uniform
Mitotic rate is usually high
Presence of multinucleated cells

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pale pink to beige circumscribed homogeneous mass. The cut surface has a gelatinous texture and bulged slightly on incision. The contralateral testis was atrophic.

Seminomas consist of round germinal cells with a high nuclear-to-cytoplasmic ratio and frequent mitoses (not shown here). Note how the cells have filled and expanded the seminiferous tubules. Inset, Higher magnification of the neoplastic cells. Note the mitoses.

Despite this “malignant” appearance, most are behaviorally benign

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Teratomas

A teratoma is a tumor made up of several different types of tissue, such as hair, muscle, teeth, or bone.
Quite uncommon but occur in young horse, especially in cryptoorchid testis.
Arises from totipotential primordial germ cells
Grossly:

Large, cystic or polycystic
Contain recognizable hair, mucus bone or even teeth

Microscopically:

Arise form three embryonic germ layers
Well differentiated

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Interstitial Endocrine cell Neoplasm

Also called Leydig cell neoplasm
Most common in bull, dog and cat
Almost always benign
Grossly:

Nodular in shape, Spherical and well demarcated
Tan to orange color, often contain regions of hemorrhage

Microscopically:

Non invasive and finely encapsulated
Cells are arranged in solid sheets by a fine fibrous stroma
Neoplastic cells are large, round and polyhedral or spindle shaped
Have vaculated cytoplasm and has brown lipofuscin pigment.
Nuclei are round and anisokaryosis is usaully minimal.

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Note the well-demarcated, yellow-tan mass, which has bulged on incision. Such masses become hemorrhagic when they become large. Atrophy of an affected testis as the result of pressure is common when the tumor is large.

Cells are arranged in packets surrounded by a fine fibrous stroma typical of endocrine cells. Their cytoplasm is pale, eosinophilic, and abundant and often has fine vacuoles. Mitoses are rare.

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Sertoli Cell Neoplasm

Third most common neoplasm of the dog.
Rare in other species
Rare metastasis

Grossly:

Well circumscribed, expansile, firm, white and lobulated
Enlargement of testies.

Microscopically:

Abundant fibrous tissue
Neoplastic cells have intratubular or a diffuse arrangement and tend to palisade along the fibrous stroma
Cells pleomorphic

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Sertoli cell tumors are firm, white, and often lobulated, and the lobules are surrounded by fibrous bands.

Sertoli cell tumors have tubular structures lined by cells that resemble Sertoli cells and are supported by fine septa of fibrous tissue.

Prostate, squamous metaplasia. Hyperestrogenism from functional Sertoli cell tumors induces hyperplasia and/or squamous metaplasia of the prostate. Normal epithelium of the prostatic ducts and glandular acini (columnar) is replaced by stratified squamous keratinizing epithelium.

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Neoplasm of Penis and prepuce

Dog: Canine Transmissible veneral tumor
Horse, bull, boar and dog: Papilloma and squamous cell carcinoma

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Penile Squamous cell carcinoma

It’s the tumor of head of penis
Etiology: Equine papillomoavirus
Grossly:

Enlarged firm penis with focal ulcers
Large ulcerated mass protudes form the glans penis
Prepuce is edematous

Microscopically:

Neoplasm is well differentiated
Develop invasive nests, cords and nodules of neoplastic epithelium with differentiation toward the stratum spinosum
Neoplastic cells are surrounded by fibrous tissue as well as lymphocytes and plasma cells

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Penile Fibropapilloma

Occur on the head of the penis of young bulls
Cause by bovine papillomavirus 1
Grossly:

Single or multiple warty masses have a papillary epithelial covering and a fibrous core
Extensive surface ulceration

Microscopically:

Epithelial and stromal hyperplasia and long projections of epithelium into the fibrous tissue.

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There is a large exophytic papillary mass protruding from the penile epithelium. This large proliferative lesion on the penis is typical of a fibropapilloma

Note the abundant connective tissue (C) covered by hyperplastic stratified squamous epithelium (E) that is thickened and has elongated epidermal-dermal interdigitations that penetrate deeply into the connective tissue.

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Canine Transmissible venereal Tumor

Primary neoplasm of external genitalia
Can metastases
Grossly:

Tumor are found on the penis more often on the proximal parts and not often on the prepuce
Neoplasm can be single or multiple
Have red ulcerated and multinodular surface.

Microscopically:

Neoplastic cells form a diffuse sheet with minimal stroma
Cells are large, round or oval and uniform in size thus resembling lymphocytes
Cytoplasm is pale staining and may have peripheral vacuoles

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There is a large multinodular mass involving the penis and the prepuce at its reflection from the penis.

Neoplastic cells are round, uniform in size, and often divided into packets by a fine fibrous stroma. Mitoses are frequent