Syphilitic Gumma (Gumma Subcutaneum), or Gummatous Syphilid

A painless nodule the size of a walnut forms in the subcutaneous tissue without adhesion with the skin or surrounding tissues. It grows gradually, fuses with the skin, and loses its mobility. The skin becomes cyanotic-red and tenderness appears. The node softens in the centre and a small opening forms from which a gummy fluid resembling gum arabic (hence the name 'gumma') is discharged. The opening grows and an ulcer with hard edges steeply inclined to the floor forms. Necrotic tissue, the gummatous core, is found on the floor of the ulcer; it separates slowly after which the ulcer cicatrizes. A deeply-seated retracted (stellate) scar forms. Much less frequently the gumma may resolve without the formation of an ulcer. The patient usually has one, rarely more gummata. The gummata usually form on the anterior surface of the legs, on the forehead, and forearms; sometimes fibrous gummata, periarticular nodules, form (mostly around the knees and elbows). On resolution the gummatous nodules grow smaller to the size of a hazel-nut and their infiltrate is replaced by fibrous tissue which lends the nodules a cartilaginous hardness. They are very resistant to specific therapy.

Tertiary syphilids (gummata and tubercles) are often localized on the mucous membranes of the nose, soft palate and uvula. In involvement of the nasal bones the bridge of the nose sinks (the nose becomes saddle back) or the bony part of the nasal septum is perforated. Because of perforation of the hard and soft palate and destruction of the uvula the voice acquires a nasal quality and food gets into the nasal cavity. Gummatous osteoperiostitis or osteomyelitis usually occurs in the tibia and skull bones. The bone becomes thickened or the infiltrate disintegrates with the formation of an ulcer, after which the tissue cicatrizes.

With the formation of gumma or tubercular syphilis the histological picture is marked by an inflammatory infiltrate of the type of infectious granuloma and pronounced changes of the blood vessels. In cases with gumma, the infiltrate is found in the subcutaneous tissue and then spreads to the dermis; in cases of tubercular syphilid, it is only found in the dermis. The infiltrate contains very many plasma cells, lymphocytes, histiocytes and a more or less considerable number of giant and epithelioid cells. Foci of necrosis are detected in the gummatous infiltrates. Proliferation of the endothelium is seen in the walls of the vessels, especially the large ones, which may lead to obliteration of the walls.

The diagnosis is very difficult in the initial developmental period of the gumma, but much easier after its ulceration (the characteristic clinical picture of gummatous ulcer) and in cases when the patient applies to the physician with a formed characteristically stellate scar.

Syphilitic gummata are differentiated from scrofuloderma. In scrofuloderma the nodules are softer, undergo total ulceration and the edges of the ulcer are soft and its floor is covered with yellowish granulations. A differential diagnosis is also made with erythema induratum (usually manifested by multiple nodules arranged symmetrically on the legs, sometimes by superficial ulcers with eroded edges) and carcinomatous ulcers (hard, elevated, swollen or 'everted' edges and an uneven easily bleeding floor).