Title: Granulomatous
Secondary Syphilis
Article type : Image challenge
A 20-year-old male presented to our clinic with multiple red, tender,
enlarging nodules on his forehead, nose, and forearm for six weeks,
accompanied by severe headaches and photophobia. Prior to the eruption
of the skin lesion, the patient had fatigue and enlarged cervical lymph
nodes. Despite taking oral prednisone 20 mg daily for four days, he
showed little improvement. Two well-defined erythematous nodules
measuring 1cm x 0.5cm were found on the forehead, with numerous others
on the upper arms (Figure 1). Nodules on the forehead were accompanied
by lymphadenopathy in the cervical region. Punch biopsy of the lesion
revealed a dense dermal granulomatous infiltrate with lymphocytes and
numerous plasma cells. Immunohistochemical staining for Treponema
pallidum identified numerous spirochetes, confirming a diagnosis of
secondary syphilis. Treatment with benzathine penicillin G resulted in
the complete resolution of symptoms.
Granulomatous inflammation, as seen in this case, is an atypical feature
of secondary syphilis. Unlike typical secondary syphilis, granulomatous
secondary syphilis usually presents with a papular or nodular rash at
onset, sparing the palms and soles.1 Most commonly,
these lesions affect the head, neck, trunk, and
extremities.1 This unusual presentation further
contributes to the difficulty in clinical
diagnosis.1 Secondary syphilis lesions may also
exhibit a sporotrichoid pattern, which may be explained by lymphatic
dissemination of Treponema pallidum .2 As
opposed to other sporothrichoid conditions, which involve the
extremities with or without associated adenopathy, sporotrichoid
secondary syphilis affects the lymph nodes of the postauricular,
occipital, and posterior cervical regions.2 Psoriasis,
viral exanthem, cutaneous lymphoma, granuloma annulare, and sarcoidosis
are among the differential diagnoses of secondary syphilis. Because of
its wide range of clinical and histopathological features, syphilis is
aptly termed the great mimicker. Histologically, plasma cell-rich dermal
infiltrates are common, whereas granulomatous inflammation is rare. It
is important to consider the diagnosis of secondary syphilis when these
histopathologic findings are corroborated by patient
history.1Serologic testing is the mainstay of
screening and diagnosing syphilis.1,2 Even though
detection of Treponema pallidum by immunohistochemistry is widely
available, it is expensive. Benzathine penicillin is the
treatment of choice for all stages of syphilis.1,2