Treponema pallidum distribution patterns in mucocutaneous lesions of primary and secondary syphilis: an immunohistochemical and ultrastructural study

Syphilis in Hematopathology Practice: A Diagnostic Challenge

CONTEXT.—

Syphilis, a reemerging disease caused by the spirochete Treponema pallidum, is becoming more frequent in surgical pathology and hematopathology practices. Hematopathologists typically receive lymph node biopsies from patients with syphilis who have localized or diffuse lymphadenopathy. Occasionally, syphilis infection in the aerodigestive tract can show a prominent lymphoplasmacytic infiltrate and mimic lymphoma. Besides the varying and occasional atypical morphology, the fact that clinical suspicion tends to be low or absent when histologic evaluation is requested adds to the importance of making this diagnosis.

OBJECTIVE.—

To summarize histologic features of syphilitic lymphadenitis and syphilis lesions in the aerodigestive tract, and to review differential diagnosis and potential diagnostic pitfalls.

DATA SOURCES.—

Literature review via PubMed search.

CONCLUSIONS.—

Characteristic histologic findings in syphilitic lymphadenitis include thickened capsule with plasma cell-rich inflammatory infiltrate, reactive follicular and paracortical hyperplasia with prominent lymphoplasmacytic infiltrate, and vasculitis. Lymph nodes, however, can show a number of other nonspecific histologic features, which frequently makes the diagnosis quite challenging. In the aerodigestive tract, syphilis is characterized by plasma cell-rich infiltrates. Immunohistochemistry for T pallidum is the preferred method for detecting spirochetes; however, this immunohistochemical stain shows cross-reactivity with other treponemal and commensal spirochetes. Differential diagnosis of syphilis in lymph nodes and the aerodigestive tract is broad and includes reactive, infectious, and neoplastic entities. Pathologists should be aware of the histologic features of syphilis and keep this challenging entity in the differential diagnosis.

Intraoral primary syphilis mimicking lymphoproliferative disorder

Syphilis can mimic, clinically and microscopically, many other diseases. By microscopy, typically syphilis presents with plasma cell infiltration, admixed with lymphocytes and macrophages, in lichenoid and/or perivascular/perineural distribution pattern. When exuberant, this inflammatory infiltrate can mimic a lymphoproliferative disorder (LPD), notably plasma cell neoplasia or lymphoma. To date, about 12 cases of secondary syphilis, all but one in extraoral location, suggesting initially a LPD, have been published. Here, to our knowledge, we report an unusual case of intraoral primary syphilis initially suggesting LPD, notably lymphoid hyperplasia (pseudolymphoma); however, mucosa-associated lymphoid tissue (MALT) lymphoma and follicular lymphoma could not be disregarded. Polyclonality of plasma cells on immunohistochemistry, in strict clinical correlation, was essential to arrive at the correct diagnosis.

Syphilis for dermatologists: Current concepts

Dermatologists are familiar with the classic aspects of syphilis. Our objective in this update is to display novel features of sexually acquired syphilis, its pathophysiology, natural history, atypical clinical variants, skin of color, clinical pearls, and prospects. Textbook knowledge, congenital syphilis, epidemiology, and historical data are excluded.

Endothelial dysfunction of syphilis: Pathogenesis

Treponema pallidum is the causative factor of syphilis, a sexually transmitted disease (STD) characterized by perivascular infiltration of inflammatory cells, vascular leakage, swelling and proliferation of endothelial cells (ECs). The endothelium lining blood and lymphatic vessels is a key barrier separating body fluids from host tissues and is a major target of T. pallidum. In this review, we focus on how T. pallidum establish intimate interactions with ECs, triggering endothelial dysfunction such as endothelial inflammation, abnormal repairment and damage of ECs. In addition, we summarize that migration and invasion of T. pallidum across vascular ECs may occur through two pathways. These two mechanisms of transendothelial migration are paracellular and cholesterol-dependent, respectively. Herein, clarifying the relationship between T. pallidum and endothelial dysfunction is of great significance to provide novel strategies for diagnosis and prevention of syphilis, and has a great potential prospect of clinical application.

Primary syphilis, an extremely uncommon cause of acute-onset phimosis

We present a case of phimosis in the context of primary syphilis with a preputial chancre. An accurate diagnosis after an appropriate examination and patient history allowed conservative treatment with antibiotics and the avoidance of circumcision in this patient.

Granulomatous Secondary Syphilis: A Case Report with a Brief Overview of the Diagnostic Role of Immunohistochemistry

The diagnosis of syphilis can be challenging for dermatologists and dermatopathologists. In particular, secondary syphilis can have different clinical and histopathological presentations. A granulomatous tissue response is an unusual finding in secondary syphilis. We report the case of a 77-year-old man who presented with a 4-week history of non-pruritic generalised macules, papules, nodules and plaques. Histopathologically, there was a dense perivascular and periadnexal lympho-histiocytic dermal infiltrate with non-palisading and non-caseifying epithelioid granulomas and abundant plasma cells. The diagnosis of syphilis was confirmed by serology and immunohistochemical detection of Treponema pallidum in the biopsy specimen. A brief overview of the diagnostic role of immunohistochemistry is also provided, with particular emphasis on reported cases of granulomatous secondary syphilis.

Immunohistochemical detection of Treponema pallidum in skin samples with clinical and histopathological correlations and Warthin-Starry staining critical analysis

BACKGROUND

Syphilis in its different phases may be a difficult diagnosis in clinical and histopathological grounds.

OBJECTIVES

The present study objectives were to evaluate the detection and tissue distribution of Treponema pallidum in skin lesions of syphilis.

METHODS

A blinded diagnostic accuracy study was performed with immunohistochemistry and Warthin-Starry silver staining in skin samples from patients with syphilis and other diseases. Patients attended two tertiary hospitals between 2000 and 2019. Prevalence ratios (PR) and 95% confidence intervals (95% CI) were calculated for the association between immunohistochemistry positivity and clinical-histopathological variables.

RESULTS

Thirty-eight patients with syphilis and their 40 biopsy specimens were included in the study. Thirty-six skin samples were used as non-syphilis controls. The Warthin-Starry technique was unable to accurately demonstrate bacteria in all samples. Immunohistochemistry showed spirochetes only in skin samples from patients with syphilis (24/40) with 60% sensitivity (95% CI 44.8‒75.2). Specificity was 100% and accuracy, 78.9% (95% CI 69.8‒88.1). Most cases had spirochetes in both dermis and epidermis and there was a high bacterial load.

STUDY LIMITATIONS

Correlation between immunohistochemistry and clinical or histopathological characteristics was observed but was limited statistically due to the small sample size.

CONCLUSIONS

Spirochetes were promptly seen in an immunohistochemistry protocol, which can contribute to the diagnosis of syphilis in skin biopsy samples. On the other hand, the Warthin-Starry technique showed to be of no practical value.

Gastric Syphilis Presenting as a Nodal Inflammatory Pseudotumor Mimicking a Neoplasm: Don’t Forget the Treponema! Case Report and Scoping Review of the Literature of the Last 65 Years

Despite the fact that gastric syphilis is considered rare, it is reported as a type of organic involvement that is present in a large proportion of secondary syphilis cases, even though gastritis presenting with symptoms is extremely rare. Clinical, radiological, and endoscopic findings are non-specific and frequently mimic the symptoms of gastric adenocarcinoma or lymphoma, making diagnosis difficult. Immunostaining is required for this diagnosis. We would like to emphasize the importance of being suspicious of GS when a gastric mass exhibits the histologic features of an inflammatory pseudotumor (IPT), as previously reported for nodal IPT caused by luetic infection. We described a 56-year-old man who presented to the oncology department with a 3-month history of anorexia, epigastric pain, nausea, vomiting, and weight loss, as well as an initial radiological and endoscopic suspicion of gastric adenocarcinoma, in which immune staining allowed us to diagnose GS. In addition, we conducted an updated scoping review of the scientific literature to show the clinical, laboratory, and therapeutic findings in GS patients over the last 65 years.

Diagnostic utility of fine-needle aspiration cytology in syphilitic lymphadenitis: A case report

Syphilis is a sexually transmitted infection that causes serious health problems without treatment. Detection of syphilis is necessary to stop the spread of the infection. Cytological screeners and pathologists may experience fine-needle aspiration cytology (FNAC) for syphilitic lymphadenitis; however, its characteristic cytological features are rarely reported. We present FNAC cytological features of syphilitic lymphadenitis in a case of a 21-year-old man. He presented with a sore throat and painful neck lymphadenopathy. His swollen and painful neck persisted even with antibiotic treatment. Necrotizing lymphadenitis and lymphoma were clinically suspected. FNAC was taken from the swollen lymph node. Cytologic findings of the specimen showed various inflammatory cells with small-sized vessels arranged in a branching/arborizing fashion. The vessels were surrounded by inflammatory cells, including plasma cells, neutrophils, and macrophages. Perivascular plasma cell cuffing was focally seen along with inconspicuous granulomas. Neutrophils appeared to involve the vascular wall. The cytological findings suggested syphilitic lymphadenitis, and clinical findings and serological tests confirmed primary syphilis with concomitant human immunodeficiency virus infection. Branching/arborizing vessels associated with many plasma cells, vascular involvement of neutrophils, and granulomas may suggest syphilitic infection if the specimen is obtained via FNAC. (189 words).

Granulomatous secondary syphilis: Another diagnostic pitfall for the dermatopathologist

Syphilis is growing ever more prevalent in the United States with its incidence rising every year. Dermatopathologists need to maintain a high index of suspicion to avoid delayed diagnosis of this treatable disease. Accordingly, it is imperative to be aware of its myriad of presentations-including secondary syphilis with granulomatous inflammation. Most cases show aggregations of epithelioid histiocytes associated with plasma cells. Other patterns include an interstitial granuloma-annulare-like pattern, sarcoidal, and tuberculoid pattern. Immunohistochemical stains for Treponema pallidum may be negative, especially in late secondary or tertiary syphilis. We present a case of nodular secondary syphilis with granulomatous inflammation with negative T. pallidum staining.

Syphilis in Dermatology: Recognition and Management

The incidence of syphilis has been increasing in the USA since 2000. Notably, the coronavirus disease 2019 pandemic negatively impacted the public health efforts to contain the spread of sexually transmitted diseases including syphilis and congenital syphilis. Clinical manifestations of syphilis are predominantly mucocutaneous lesions, thus dermatologists are primed to recognize the myriad presentations of this disease. Primary syphilis is classically characterized by a painless transient chancre most often located in the genital area. Secondary syphilis typically manifests clinically as systemic symptoms in addition to a mucocutaneous eruption of which a variety of forms exist. Although less common in the era of effective penicillin treatment, late clinical manifestations of syphilis are described as well. In addition to recognition of syphilis on physical examination, several diagnostic tools may be used to confirm infection. Treponema pallidum spirochetes may be detected directly using histopathologic staining, darkfield microscopy, direct fluorescent antibody, and polymerase chain reaction assays. A table detailing the histopathologic features of syphilis is included in this article. Serologic testing, non-treponemal and treponemal tests, is the preferred method for screening and diagnosing syphilis infections. Two serologic testing algorithms exist to aid clinicians in diagnosing positive syphilis infection. Determining the correct stage of syphilis infection combines results of serologic tests, patient history, and physical examination findings. Using the current Centers for Disease Control and Prevention case definitions and treatment guidelines, a management algorithm is proposed here. Penicillin remains the pharmacological treatment of choice although specific clinical situations allow for alternative therapies. Syphilis is a reportable disease in every state and should be reported by stage according to individual state requirements. Screening recommendations are largely based upon risks encountered through sexual exposures. Likewise, sexual partner management includes evaluating and treating persons exposed to someone diagnosed with an infective stage of syphilis. Close clinical follow-up and repeat testing are recommended to ensure appropriate response to treatment. This guide will discuss the current epidemiology of syphilis and focus on practice aspects of diagnosis and management, including public health reporting.

Primary syphilis presenting as a painful unilateral inguinal lymphadenopathy, without cutaneous manifestations, in a 71-year-old Japanese man: A case report

Syphilitic infection is usually observed in young patients, and the first stage of the disease (primary syphilis) is characterized by painless cutaneous and lymph node lesions. Herein, we describe a 71-year-old Japanese man with primary syphilis that presented as unilateral inguinal lymphadenopathy without skin lesions. Originally, an incarcerated hernia was clinically suspected. The lymph node pathologically showed suppurative lymphadenitis with vague granulomas; immunohistochemistry was highly suggestive of a syphilitic infection. Primary syphilis was confirmed by positive serological tests. Syphilitic infection should be included in the clinicopathological differential diagnoses for patients with inguinal lymphadenopathy, even in elderly patients without skin lesions.

Immunohistochemical diagnosis of human infectious diseases: a review

BACKGROUND

Immunohistochemistry (IHC) using monoclonal and polyclonal antibodies is a useful diagnostic method for detecting pathogen antigens in fixed tissues, complementing the direct diagnosis of infectious diseases by PCR and culture on fresh tissues. It was first implemented in a seminal publication by Albert Coons in 1941.

MAIN BODY

Of 14,198 publications retrieved from the PubMed, Google, Google Scholar and Science Direct databases up to December 2021, 230 were selected for a review of IHC techniques, protocols and results. The methodological evolutions of IHC and its application to the diagnosis of infectious diseases, more specifically lice-borne diseases, sexually transmitted diseases and skin infections, were critically examined. A total of 59 different pathogens have been detected once in 22 different tissues and organs; and yet non-cultured, fastidious and intracellular pathogens accounted for the vast majority of pathogens detected by IHC. Auto-IHC, incorporating patient serum as the primary antibody, applied to diseased heart valves surgically collected from blood culture-negative endocarditis patients, detected unidentified Gram-positive cocci and microorganisms which were subsequently identified as Coxiella burnetii, Bartonella quintana, Bartonella henselae and Tropheryma whipplei. The application of IHC to ancient tissues dated between the ends of the Ptolemaic period to over 70 years ago, have also contributed to paleomicrobiology diagnoses.

CONCLUSION

IHC plays an important role in diagnostic of infectious diseases in tissue samples. Paleo-auto-IHC derived from auto-IHC, is under development for detecting non-identified pathogens from ancient specimens.

Gastric syphilis and its importance for a differential diagnosis in HIV patients

A 41-year-old male, with history of HIV presented to emergency department with two months of abdominal pain and a weight loss. Radiological and endoscopic examinations where suggestive of gastric cancer. However, biopsies ruled out malignancy. The reaginic and anti-treponemal tests were positive, so the histological study was repeated with anti-Treponema pallidum monoclonal antibodies. The presence of spirochetes was confirmed. After three weeks of penicillin-based treatment, the gastric lesions and symptoms were resolved.

Ocular syphilis

Multiple studies around the world suggest that syphilis is re-emerging. Ocular syphilis - with a wide range of presentations, most of which are subtypes of uveitis - has become an increasingly common cause of ocular inflammation over the past 20 years. Its rising incidence, diagnostic complexity, and manifestations that have only recently been characterized make ocular syphilis relevant from the public health, clinical, and scientific perspectives. We review the demographics, epidemiology, clinical features, ocular imaging findings, diagnosis, and medical management of this condition.

Oral Manifestations of Syphilis: a Review of the Clinical and Histopathologic Characteristics of a Reemerging Entity with Report of 19 New Cases

BACKGROUND

Syphilis is a sexually-transmitted infectious disease caused by Treponema pallidum. Cases of primary and secondary syphilis are on the rise in the United States, with a 14.4% increase in new cases noted from 2017 to 2018 and an escalation of 71% between the years 2014 and 2018. Fulfilling its nickname of "the great imitator," oral manifestations of syphilis may mimic a variety of infectious, neoplastic, or immune-mediated processes, both clinically and histopathologically. This large spectrum of appearances can create a diagnostic challenge to the clinician and/or pathologist, leading to delay in diagnosis or misdiagnosis.

METHODS

A database of oral syphilis cases was created from archives at the University of Kentucky, University of Pittsburgh, LIJMC, Columbia University MC, and University of Tennessee. The age, sex, race, location, duration, and clinical description were recorded. Cases without positive reaction upon immunohistochemistry or serologic tests were excluded.

RESULTS

We identified 19 new cases of oral syphilis (17 males, one female, and one case unknown sex) and described the clinical and histopathological features of this re-emerging and potentially fatal disease. All cases demonstrated dense lymphoplasmacytic inflammation, often with inflammatory exocytosis or ulceration at the surface, and perivascular inflammation.

CONCLUSIONS

Early recognition of the histopathologic and clinical manifestations of oral syphilis is imperative for prompt diagnosis, improved patient outcomes, and disease prevention.

Secondary syphilis mimicking sarcoidosis

Secondary syphilis may mimic sarcoidosis due to atypical clinical and pathological presentations. Differential diagnosis of these two is critical since the clinical courses and treatments are different. Highly clinical suspicion and utilization of confirmatory tests in high-risk patients are the key for the differential diagnosis.

Update in Infectious Disease Diagnosis in Anatomic Pathology

Anatomic pathology is an important resource for detection and exclusion of infectious diseases in tissue specimens. Detection of a microorganism (i.e. bacteria, fungi, parasite) in tissue sections is frequently the beginning of a work-up and occasionally sufficient for definitive microbiologic identification. Close correlation with cultures and ancillary testing in the microbiology laboratory is of paramount importance in arriving at a diagnosis and identify with certitude causative pathogen(s). This review will discuss the adequacy and limitations of histopathology in the diagnosis of infectious diseases, describe potential pitfalls, and discuss the appropriate use of molecular diagnostics in formalin-fixed, paraffin embedded tissues.

Syphilis in Pregnancy

Despite a national plan to eliminate syphilis by 2005, recent trends have reversed previously achieved progress in the United States. After a nadir between 2000 and 2013, rates of primary and secondary syphilis among women and congenital syphilis rose by 172% and 185% between 2014 and 2018, respectively. Screening early in pregnancy, repeat screening in the third trimester and at delivery among women at high risk, adherence to recommended treatment regimens, and prompt reporting of newly diagnosed syphilis cases to local public health authorities are strategies that obstetrician-gynecologists can employ to fight the current epidemic. In this report, clinical manifestations and management of syphilis in pregnancy are reviewed, and both traditional and reverse sequence screening algorithms are reviewed in detail in the context of clinical obstetrics.

Clinicopathological, dermoscopic, and ultrastructural observation of annular secondary syphilis on the penis

Annular syphilis may range from mildly raised lesions with scaly borders to verrucous plaques. Localized annular syphilis on the genitalia has been rarely reported in HIV-negative cases. This paper reports a case of annular secondary syphilis on the penis. Dermoscopy showed peripheral dotted and short linear vessels and white scaling with a relatively clear central area in an erythematous annular plaque. Histopathology revealed mild hyperkeratosis, parakeratosis, psoriasiform acanthosis, and focal basal vacuolar degeneration with lichenoid, perivascular, and periadnexal infiltrate of lymphohistiocytes and plasma cells in the superficial dermis. Silver stain showed several spirochetes in the lower epidermis and superficial dermis. Electron microscopy revealed a few intercellular and intracytoplasmic spirochetes in the basal epidermis and free spirochetes in the papillary dermis. Rapid plasma reagin and Treponema pallidum particle agglutination assays were positive. The lesions disappeared after intramuscular benzathine penicillin, with no relapse at six-month follow-up.

Histologic Features of Secondary Syphilis

BACKGROUND

Secondary syphilis is a sexually transmitted infection, which is referred to as "the great imitator" and has a wide spectrum of clinical manifestations. As a result, it is essential to identify potential secondary syphilis patients with ambiguous clinical manifestation through pathology.

OBJECTIVE

We sought to analyze the pathological features of secondary syphilis.

METHODS

We analyzed 59 biopsy specimens from 56 patients with secondary syphilis. Cases were classified according to the histological characteristics and clinical features.

RESULTS

Necrotic keratinocytes could be observed in 39 of 59 (66.1%) secondary specimens. Plasma cells (86.4%) were the most common finding overall. The presence of Treponema pallidum was detected mostly at the dermal-epidermal junction. There was no statistical significance between pathological features and age, HIV status, or RPR titer.

CONCLUSIONS

Necrotic keratinocytes are one of the characteristics of secondary syphilis. The combination of plasma cells, irregular acanthosis, elongated rete ridges, and endothelial swelling should increase the likelihood of syphilis.

Treponema pallidum Induces the Secretion of HDVSMC Inflammatory Cytokines to Promote the Migration and Adhesion of THP-1 Cells

The pathological features of syphilis, a disease caused by Treponema pallidum (T. pallidum), are characterized by vascular involvement with endarteritis and periarteritis. Little is known about the interactions of infiltrating immunocytes with human dermal vascular smooth muscle cells (HDVSMCs) in arterioles during the immunopathogenesis of syphilis. In the present study, we demonstrated that stimulation of HDVSMCs with T. pallidum resulted in the upregulated gene transcription and protein expression of interleukin (IL)-6, monocyte chemoattractant protein-1 (MCP-1), and intercellular adhesion molecule-1 (ICAM-1) in a dose- and time-dependent manner. Moreover, the migration and adhesion of THP-1 cells to HDVSMCs were significantly suppressed by anti-MCP-1 and anti-ICAM-1 neutralizing antibodies, respectively. Further studies revealed that T. pallidum activated the NF-κB signaling pathway in HDVSMCs. Inhibition of NF-κB suppressed T. pallidum-induced IL-6, MCP-1, and ICAM-1 expression. In addition, the migration and adhesion of THP-1 cells to T. pallidum-treated HDVSMCs were significantly decreased by pretreatment with an NF-κB inhibitor. These findings demonstrate that T. pallidum induces the production of IL-6, MCP-1, and ICAM-1 in HDVSMCs and promotes the adherence and migration of THP-1 cells to HDVSMCs through the NF-κB signaling pathway, which may provide new insight into the pathogenesis of T. pallidum infection.

Recombinant Treponema pallidum protein Tp47 promotes the migration and adherence of THP-1 cells to human dermal vascular smooth muscle cells by inducing MCP-1 and ICAM-1 expression

Vascular inflammation is a complex and multifactorial pathophysiological process that plays a crucial role in all stages of syphilis and is responsible for tissue damage. Little is known about the interactions of infiltrating immunocytes with human dermal vascular smooth muscle cells (HDVSMCs) in arterioles during the immunopathogenesis of syphilis. The Treponema pallidum subsp. pallidum membrane protein Tp47 is considered a major inducer of inflammation initiation and development. In this study, we demonstrated that Tp47 promoted the migration and adhesion of THP-1 cells to HDVSMCs. Furthermore, Tp47 increased monocyte chemoattractant protein-1 (MCP-1) and intercellular adhesion molecule-1 (ICAM-1) mRNA and protein expression levels in a dose- and time-dependent manner. The migration and adhesion of THP-1 cells to HDVSMCs were significantly suppressed by anti-MCP-1 and anti-ICAM-1 neutralizing antibodies, respectively. Further studies revealed that treatment of HDVSMCs with Tp47 activated the PI3K/Akt, p38 MAPK and NF-κB signalling pathways. Inhibition of PI3K/Akt, p38 MAPK and NF-κB suppressed the MCP-1 and ICAM-1 expression induced by Tp47. In addition, the migration and adhesion of THP-1 cells to Tp47-treated HDVSMCs were significantly decreased by pretreatment with PI3K/Akt, p38 MAPK and NF-κB inhibitors. These findings demonstrate that Tp47 promotes the migration and adherence of THP-1 cells to HDVSMCs by inducing MCP-1 and ICAM-1 expression, which is mediated by activation of the PI3K/Akt, p38 MAPK and NF-κB pathways. This study provides a novel potential therapeutic strategy for controlling the vascular inflammatory response in syphilis patients.

Sexually acquired syphilis: Laboratory diagnosis, management, and prevention

The methods used for the laboratory diagnosis of syphilis include direct detection of Treponema pallidum subspecies pallidum and serologic testing. Serologic testing relies on both nontreponemal and treponemal tests. In newly developed reverse-sequence screening algorithms, treponemal tests are performed before nontreponemal tests. The management of syphilis requires appropriate staging, treatment, and follow-up of patients along with the prompt reporting of infections to public health authorities to assist with prevention and control efforts. Benzathine penicillin G remains the treatment of choice for all stages of syphilis. Screening of populations at higher risk for syphilis is recommended by the US Centers for Disease Control and Prevention, the US Preventive Services Task Force, and the World Health Organization. The second article in this continuing medical education series reviews the testing for and the management of sexually acquired syphilis.

Syphilis of the Aerodigestive Tract

Syphilis, a sexually transmitted infection caused by the Gram-negative bacterium Treponema pallidum, is increasing in prevalence in the United States. It has been our experience that primary and secondary syphilis of the aerodigestive tract can afflict a large age spectrum with varied clinical and histopathologic findings, which can lead to diagnostic problems and frequent misdiagnosis. In this study, we describe the histopathologic patterns of syphilis of the aerodigestive tract to expand awareness of its varied appearance. We identify 3 patterns of inflammatory response to syphilis: plasma cell-rich, lymphohistiocytic, and lymphoma-like. We also report the presence of immunoglobulin G4-predominant plasma cells in the inflammatory response as a potential mimicker of immunoglobulin G4-related disease. Lastly, we found that use of T. pallidum immunohistochemical stain is more reliable than Steiner silver stain at the identification of spirochetes. Our study highlights that despite convention, plasma cells are not always abundant in syphilis. Awareness of the histopathologic range of syphilis in the aerodigestive tract by the surgical pathologist can lead to the correct diagnosis and guide appropriate treatment.

What's New in Dermatopathology: Inflammatory Dermatoses

Inflammatory skin diseases encompass a vast array of conditions. The field continues to expand and evolve with resurgence of conditions, through newly recognized medication adverse effects, and via more detailed descriptions of known dermatoses. The importance of clinicopathologic correlation and an up to date knowledge of dermatologic conditions cannot be overstated. This review focuses on an array of recent important developments in the histologic diagnosis of inflammatory conditions that affect the skin.

Secondary syphilis primarily presenting with multiple nodules on the scalp: Case report and published work review

Syphilis, a sexually transmitted disease caused by Treponema pallidum, manifests with a broad spectrum of clinical presentations that usually involves skin. Nodular secondary syphilis occurs rarely, and mostly manifests as disseminated papulonodules or plaques over the trunk and limbs. We report an extremely rare case of nodular secondary syphilis that primarily presented with multiple nodules on the scalp, resembling Rosai-Dorfman disease or cutaneous malignant metastasis. Immunohistochemistry confirmed T. pallidum spirochetes microscopically.

Papulonodular secondary syphilis: a rare clinic presentation confirmed by serologic and histologic exams

Syphilis is a sexually transmitted disease caused by Treponema pallidum and divided into three stages according to the duration of the disease: primary, secondary and tertiary. Secondary syphilis has diverse clinical presentations, such as papular-nodular lesions. This presentation is rare, with 15 cases reported in the literature over the past 20 years. We report a case of secondary syphilis with papular-nodular lesions in a healthy 63-year-old patient, who has presented treponema in immunohistochemical examination of the skin lesions.

Syphilis associated with paretic neurosyphilis mimicking Reiter's syndrome in HIV-infected patients

HIV/syphilis co-infection is common because both conditions affect similar risk groups. HIV interferes with the natural history of syphilis, which often has atypical clinical features and nervous system involvement in the early stage of disease. We report the case of an HIV-positive patient with secondary syphilis, scaling palmoplantar keratoderma, scrotal eczema, balanitis and urethritis mimicking Reiter’s syndrome. Immunohistochemistry using polyclonal antibodies against Treponema pallidum revealed the presence of spirochetes, associated with the paretic form of parenchymal neurosyphilis. The patient was given crystalline penicillin, with complete resolution of dermatological and neurological symptoms, and no sequelae.

Unusual primary syphilis: Presentation of a likely case with a review of the stages of acquired syphilis, its differential diagnoses, management, and current recommendations

Syphilis is an ancient disease that has re-emerged in the last decade. It is prevalent among men who have sex with men and has increased in incidence with certain ethnic groups. It usually presents as primary or secondary syphilis and can progress to tertiary syphilis if not treated. Primary syphilis will classically manifest as a single, painless ulcer with smooth, clean, and raised borders on the genitals or less often on the oral mucosa. Unusual primary syphilis cases have been reported and can be easily misdiagnosed with a resulting delay of treatment. Secondary syphilis is a systemic disease, wherein the treponemes have disseminated to various organ systems, typically presenting with characteristic mucocutaneous lesions. Tertiary syphilis has a higher rate of morbidity and mortality; as such, the aim of this article is to provide the readers with tools to recognize early syphilis and prevent its progression to late stages. In this review, we present a likely case of unusual primary syphilis mimicking herpes progenitalis as well as a compilation of all atypical cases of primary syphilis from 1973 to 2015. We will also review the differential diagnosis, management, and recommendations for each stage of syphilis.

Human immunodeficiency virus-positive secondary syphilis mimicking cutaneous T-cell lymphoma

Malignant syphilis or lues maligna is a severe form of secondary syphilis that was commonly reported in the pre-antibiotic era, and has now reemerged with the advent of the human immunodeficiency virus (HIV) epidemic. However, the characteristic histopathological findings of malignant syphilis remain controversial. The aim of this case report was to clarify the clinical and histopathological findings of HIV-positive malignant secondary syphilis. A Japanese man in his forties complained of fever, skin lesions, headache, and myalgia without lymphadenopathy during the previous 4 weeks. The skin lesions manifested as erythematous, nonhealing, ulcerated papules scattered on his trunk, extremities, palm, and face. Although the skin lesions were suspected to be cutaneous T-cell lymphomas on histological analyses, they lacked T-cell receptor Jγ rearrangement; moreover, immunohistochemical analyses confirmed the presence of spirochetes. The patient was administered antibiotics and anti-retroviral therapy, which dramatically improved the symptoms. On the basis of these observations of the skin lesions, we finally diagnosed the patient with HIV-associated secondary syphilis that mimicked cutaneous T-cell lymphoma. The patient’s systemic CD4+ lymphocyte count was very low, and the infiltrate was almost exclusively composed of CD8+ atypical lymphocytes; therefore, the condition was easily misdiagnosed as cutaneous lymphoma. Although the abundance of plasma cells is a good indicator of malignant syphilis on skin histological analyses, in some cases, the plasma cell count may be very low. Therefore, a diagnosis of malignant secondary syphilis should be considered before making a diagnosis of primary cutaneous peripheral T-cell lymphoma or lymphoma associated with HIV infection.

Immunohistochemistry in the diagnosis of cutaneous bacterial infections

The identification of pathogens is of vital importance for the adequate treatment of infections. During the past 2 decades, the approach to histopathologic diagnosis has been dramatically transformed by immunohistochemistry (IHC) specifically in the diagnosis and classification of tumors and more recently in the diagnosis of infectious diseases in tissue samples. The main goals of this article were to: (1) identify by IHC the cutaneous structures where bacterial pathogens are expressed in the course of infection, (2) identify the specific cells in which bacterial pathogens are expressed in positive cases, and (3) describe the pattern of distribution of the bacterial antigens within these cells (nuclear, cytoplasmatic, or membranous). This article is an up-to-date overview of the potential uses and limitations of IHC in the histopathologic diagnosis of cutaneous bacterial infections. In conclusion, IHC is especially useful in the identification of microorganisms that are present in low numbers, stain poorly, are fastidious to grow, culture is not possible, or exhibit an atypical morphology.

Diagnostic approaches in unsuspected oral lesions of syphilis

Awareness of the increased prevalence of syphilis is essential for early diagnosis and treatment, and to prevent the spread of the disease. Although serological studies are the primary tool used to confirm the diagnosis of secondary syphilis, biopsy of unsuspected oral lesions is not uncommon in the routine oral pathology laboratory. In these cases, histopathological characteristics are likely to indicate the possibility of syphilis, and an immunohistochemical reaction can confirm it. The aim of the present study was to highlight the histological features and test the efficacy of immunohistochemistry in the detection of Treponema pallidum in oral lesions biopsied with the assumption of a non-syphilitic disease. Thirty-nine tissue samples from patients for whom the possibility of syphilis was suggested on the basis of histopathological findings, were retrieved from the surgical oral pathology service files and submitted to immunohistochemical staining for T. pallidum. The study was approved by the institutional ethics committee. Eighteen of the tissue samples were positive for T. pallidum. Following this, the contributing clinicians were contacted to check whether they had asked for serological examinations when the diagnostic report was received; for all 18 positive cases, the clinicians confirmed that the patients had tested positive at that time. This study shows the importance of clinical-pathological correlation and the value of immunohistochemistry in the diagnosis of unsuspected syphilis.

Pathologically confirmed malignant syphilis using immunohistochemical staining: report of 3 cases and review of the literature

Malignant syphilis is a rare ulcerative variety. In the classical description of the disease, the absence of spirochetes in tissue samples was considered as a diagnostic criterion. We report 3 cases of malignant syphilis; in all of them, spirochetes were identified in cutaneous biopsy samples using immunohistochemical staining.

Newly Available Antibodies With Practical Applications in Surgical Pathology

Selected antibodies that have become available in recent years and have applications in diagnostic pathology are discussed. They include antibodies that are organ-related, provide information on cellular differentiation or histogenetic type, have predictive value in tumors, and highlight infective agents. PAX8 (paired box gene 8) is a marker expressed in the lower female genital tract, thyroid, and kidney and their tumors. Napsin A is expressed in the lung and kidney and is an alternative marker for pulmonary adenocarcinoma. Arginase A is a sensitive and specific marker for liver tumors. ERG (Ets-related gene) is an excellent marker for endothelium and vascular tumors as well as prostatic cancer (about 50% of cases). SOX10 (SRY-related HMG box) is expressed predominantly in melanocytic and Schwann cells and the corresponding tumors. DOG1 (discovered on GIST 1) is an excellent marker for gastrointestinal stromal tumor (GIST) and acinic cell carcinoma. OCT3/4 is a pan–germ cell tumor marker, except yolk sac tumor. SALL4 is positive in various types of germ cell tumors, including yolk sac tumor. MUC4 (mucin-related antigen 4) is a sensitive and specific marker for low-grade fibromyxoid sarcoma. Langerin is a specific marker for Langerhans cells and their tumors. SOX11 is a sensitive marker for mantle cell lymphoma. New generation antibodies against anaplastic lymphoma kinase (ALK) are required to reliably demonstrate ALK gene translocation in pulmonary carcinomas. Lack of expression of succinate dehydrogenase B is seen in paragangliomas of the hereditary form and in the pediatric type of GIST. Antibodies against Trepenoma pallidum can facilitate the diagnosis of syphilis, whereas those against SV40 (simian virus 40) are helpful for diagnosis of BK virus infection and progressive multifocal leukoencephalopathy.