**11. Fournier's gangrene**

Fournier's gangrene is a special form of fulminant cellulitis (fatal gangrene) involving the male scrotum and perineum [106–109]. The necrotizing change rapidly progresses to the surrounding soft tissue, eventually resulting in septicemia.

The prognosis is poor. The scrotum is markedly swollen and becomes reddish-black in color (**Figure 37**). The penis is either involved or spared. The physiological lack of subcutaneous fat tissue in the scrotum and penis accelerates the bacterial spread. Gas production and malodor may be associated. It belongs to non-clostridial gas gangrene when gas production is noted. The preferred age ranges from 50 to 80 years. Male patients of Fournier's gangrene often have a history of diabetes mellitus. Immunocompromised condition also accelerates the disease. Perianal abscess should be a risk factor of the disease. Masturbation-related minor penile

Aeromonas hydrophila *infection (H&E). Septic and necrotic/hemorrhagic lesions are seen in the rectal submucosa (left) and epididymis (right). Septic embolism is noted in the rectum, while Gram-negative rods are clustered around the dilated and thrombosed vascular structure in the epididymis, where inflammatory reaction*

Aeromonas hydrophila *infection in a diabetic male patient aged 50's (gross appearance). Lethal gangrene is observed on the right upper arm. Vesicular skin change is evident. Autopsy confirmed that septicemia caused*

Microscopically, massive necrosis of the skin tissue is evident. Mixed bacterial infection, including *Streptococcus* and anaerobic bacteria, is often proven. When streptococci are isolated, it is categorized in fulminant streptococcal infection (**Figure 38**). Secondary surface infection of *Trichosporon* spp. (an opportunistic

skin injury may cause the disease in younger age [110].

fungal pathogen) may occur.

**Figure 35.**

*Pathology of Gangrene*

*DOI: http://dx.doi.org/10.5772/intechopen.93505*

**Figure 36.**

*is sparse.*

**119**

*multiorgan abscess formation (see Figure 36).*

#### **Figure 34.**

Vibrio vulnificus *infection in a cirrhotic male patient (H&E and Giemsa). In a biopsy specimen sampled in an emergency suite, perivascular cuffing by infected microbes is observed around small vessels and sweat glands (arrowhead) in the deep dermis through subcutis. Coccoid transformation is recognized in H&E and Giemsa stained preparations. Inflammatory reaction is sparse. Gram stain showed negativity.*

#### **Figure 35.**

Gas formation is not associated. The traumatic infection of *V. vulnificus* is caused by an accidental trauma of the hand or fingers during cooking raw fish (preparing sashimi) or injuring the foot on the rocky seacoast. The prognosis is better than the former. The incidence of infection of the halophilic pathogen nicknamed "flesh-

Microscopically, perivascular cuffing of Gram-negative bacteria, showing a coccoid change, is noted in the involved ischemic/necrotic skin and soft tissue,

Lethal gangrene of the extremities or face is also caused by *Aeromonas hydrophila* in patients under an immunocompromised condition, with diabetes mellitus or on hemodialysis, as a form of opportunistic infection [100–104]. The bacteria invade the skin via a minor trauma. **Figure 35** illustrates gross features of lethal gangrene of the right upper arm caused by *A. hydrophila*. Vesicles are formed on the necrotic skin. *A. hydrophila* belongs to the family *Vibrio* and widely distributes in fresh water and soil. *A. hydrophila* can grow at low temperature to cause food poisoning (watery or bloody diarrhea) due to production of heat-labile enterotoxins. An outbreak of *A. hydrophila* wound infection has also been reported among the participants for mud football games in Australia [105]. There were many infected scratches and

Microscopically, the lesion shows clusters of Gram-negative rods around necrotic subcutaneous tissue. Cellular reaction is poor. Gas formation may be associated. In the case as shown in **Figure 36**, necrotizing foci of infection were

Fournier's gangrene is a special form of fulminant cellulitis (fatal gangrene) involving the male scrotum and perineum [106–109]. The necrotizing change rapidly progresses to the surrounding soft tissue, eventually resulting in septicemia.

Vibrio vulnificus *infection in a cirrhotic male patient (H&E and Giemsa). In a biopsy specimen sampled in an emergency suite, perivascular cuffing by infected microbes is observed around small vessels and sweat glands (arrowhead) in the deep dermis through subcutis. Coccoid transformation is recognized in H&E and Giemsa*

*stained preparations. Inflammatory reaction is sparse. Gram stain showed negativity.*

disseminated in the rectum, epididymis, prostate, liver, and kidneys.

eating bacteria" is high in Japan.

*Pathogenic Bacteria*

**10.3** *Aeromonas hydrophila* **infection**

pustules distributed over the bodies.

**11. Fournier's gangrene**

**Figure 34.**

**118**

while the cellular reaction is minimal (**Figure 34**).

Aeromonas hydrophila *infection in a diabetic male patient aged 50's (gross appearance). Lethal gangrene is observed on the right upper arm. Vesicular skin change is evident. Autopsy confirmed that septicemia caused multiorgan abscess formation (see Figure 36).*

#### **Figure 36.**

Aeromonas hydrophila *infection (H&E). Septic and necrotic/hemorrhagic lesions are seen in the rectal submucosa (left) and epididymis (right). Septic embolism is noted in the rectum, while Gram-negative rods are clustered around the dilated and thrombosed vascular structure in the epididymis, where inflammatory reaction is sparse.*

The prognosis is poor. The scrotum is markedly swollen and becomes reddish-black in color (**Figure 37**). The penis is either involved or spared. The physiological lack of subcutaneous fat tissue in the scrotum and penis accelerates the bacterial spread. Gas production and malodor may be associated. It belongs to non-clostridial gas gangrene when gas production is noted. The preferred age ranges from 50 to 80 years. Male patients of Fournier's gangrene often have a history of diabetes mellitus. Immunocompromised condition also accelerates the disease. Perianal abscess should be a risk factor of the disease. Masturbation-related minor penile skin injury may cause the disease in younger age [110].

Microscopically, massive necrosis of the skin tissue is evident. Mixed bacterial infection, including *Streptococcus* and anaerobic bacteria, is often proven. When streptococci are isolated, it is categorized in fulminant streptococcal infection (**Figure 38**). Secondary surface infection of *Trichosporon* spp. (an opportunistic fungal pathogen) may occur.

#### **Figure 37.**

*Fournier's gangrene (gross findings of two male cases). Massive hemorrhagic necrosis started from the scrotum and extended to the left hip and leg (left). Marked black swelling of the scrotum is serious, and necrotizing change extends toward the perianal region (right). The rapidly progressive gangrene caused death in both patients. The penis is spared in the left case, but massively involved in the right case.*

#### **Figure 38.**

*Fournier's gangrene (gross, H&E, Gram and immunostain). Debridement specimen discloses massive transmural necrosis of the scrotal tissue. Gas bubbles are scattered in the heavily infected necrotic tissue. Grampositive cocci are immunoreactive for streptococcal antigens. This case represents fulminant streptococcal infection with gas formation (non-clostridial gas gangrene).*

As illustrated in **Figure 39**, fulminant necrotizing inflammation involved the lower part of the rectum in a female patient suffering from myelodysplastic syndrome. Emergency surgery disclosed transmural gangrenous necrosis of the rectal wall with massive mixed bacterial infection, including *E. coli*. Occasionally, Fournier's gangrene has been complicated with rectal cancer [111, 112].

surgical procedures. Diabetes mellitus, immunosuppression, alcoholism, drug abuse, atherosclerosis-related ischemia, and malnutrition may be prodromal to this troublesome condition. It may be seen in healthy persons [118]. Necrotizing fasciitis

*Necrotizing fasciitis (gross and H&E). Deep and painful ulceration is caused by local and invasive bacterial infection. This aged male diabetic case had a history of arterial replacement therapy for atherosclerosis obliterans. In order to relieve pain and to avoid septicemic spread of infection, amputation surgery was*

*Lethal Fournier's gangrene of the rectum (gross, H&E and immunostain). Transmural necrotic and gangrenous inflammation is seen in the lower part of the rectum in a female patient aged 60's suffering from myelodysplastic*

*syndrome. Gram-negative rods are immunoreactive for* E. coli*-related lipopolysaccharide.*

In **Figure 41**, necrotizing fasciitis seen in a poorly controlled diabetic male patient is presented. In the wintertime, a fan heater gave the patient a severe burn on his sole, because he did not feel pain sensation due to diabetic peripheral neuropathy. The doctor-shy patient did not visit a hospital for 1 week, and this allowed the lesion far progressed. Severe atherosclerosis had provoked dry gangrene in his

is categorized into two types: type I (polymicrobial infection) and type II

*performed. Necrotizing inflammation extends to the striated muscle layer.*

(monobacterial infection).

**Figure 39.**

*Pathology of Gangrene*

*DOI: http://dx.doi.org/10.5772/intechopen.93505*

**Figure 40.**

**121**
