Arteriovenous malformation with hair collar sign

We report the case of a newborn who was noted at birth to have an occipital scalp nodule presenting with a hair collar sign (HCS). The nodule had enlarged since birth. An MRI revealed a soft tissue mass on the occipital scalp without deep extension or cranial bone involvement. A biopsy of the nodule led to a diagnosis of arteriovenous malformation (AVM). A vascular malformation with HCS has not been reported before in North America. This case highlights the complexity of diagnosing a lesion with a hair collar sign.

Direct Immunofluorescence of Skin and Oral Mucosa: Guidelines for Selecting the Optimum Biopsy Site

Direct immunofluorescence is a vital diagnostic test for assessing vesiculobullous disorders, vasculitides, and connective tissue diseases. It is a robust and valuable technique that offers essential diagnostic information for many critical dermatoses. Dermatopathologists depend heavily on the data obtained from direct immunofluorescence evaluation to confirm final diagnoses. Selecting the most appropriate biopsy site is necessary for maximizing diagnostic accuracy, and the best site may vary depending on the clinical differential diagnosis. Inaccurate biopsy site selection can significantly impact the accuracy of the results. To optimize the use of direct immunofluorescence studies, this review provides helpful guidelines and some practical tips for selecting the best biopsy site.

Cutaneous Syncytial Myoepithelioma: A Unique Variant Worth Recognizing

Cutaneous syncytial myoepithelioma is a recently characterized variant of cutaneous myoepithelioma with a distinct histopathological and immunohistochemical profile. It is more common in men and predominately involves upper and lower extremities. Microscopically, it is a dermal tumor with a characteristic solid syncytial growth pattern displaying positivity with EMA and S100 immunohistochemical stains. Lately, EWSR1-PBX3 fusion has been documented in a vast majority. Although it follows a benign clinical course, its histopathological differential diagnosis includes clinically aggressive neoplasia. This contribution summarizes the derivation, clinical presentation, histopathological and immunohistochemical features, molecular genetics, pertinent differential diagnosis, and behavior of this unique cutaneous appendageal tumor.

Normocomplementemic urticarial vasculitis in a patient with multiple sclerosis on glatiramer acetate

Glatiramer acetate is one of the oldest and safest disease modifying therapies used to treat relapsing-remitting multiple sclerosis. Urticarial vasculitis is a rare complication of treatment with glatiramer acetate, having been reported by only two others previously. Here, we describe a case of normocomplementemic urticarial vasculitis diagnosed on skin punch biopsy in a patient with multiple sclerosis treated with glatiramer acetate for five years. Upon treatment with steroids and an antihistamine along with discontinuation of glatiramer acetate, the urticaria resolved.

Diversity in dermatology: International medical graduates and their role in the diversity of a specialty

A diverse medical workforce improves patient care. Dermatology is the second-least diverse medical specialty in the United States, and many recent publications have discussed the different reasons and possible solutions to improve this disparity. A quarter of physicians in the United States are international medical graduates, which directly affects the cultural diversity in health care. Dermatology has the lowest percentage of international medical graduates in its active physician workforce. Among other measures, the inclusion of more international medical graduates in residency programs can help improve the diversity in this specialty and alleviate any disparities in dermatological care delivery in underserved communities.

Ageing population and society: a scientometric analysis

The ageing population and society (APS) nexus is one of the key grand challenges of this millennium. And yet, the systematic analysis of scholarly literature on the APS nexus has remained under the radar. This study responds to this gap and employs a quantitative approach through a scientometric analysis of literature on the APS nexus to inform policy discussions and guide future research directions. This study adopts quantitative scientometric methods to examine the APS literature (n = 566) between 2011 and 2020 found in the Scopus database. The analysis reveals key research topics and recognizes the most important articles, authors, publication outlets, institutions, and countries in the field. The findings indicate that while issues such as ageing population, gender, quality of life, and socio-economic aspects of ageing have received significant interest, social exclusion of older adults, age diversity, social policy, and the eldercare workforce have received less attention. As challenges associated with the APS nexus will continue to gain currency in the future, this paper discusses the implications of the findings on (a) future research direction and (b) north-south research collaboration. The analysis shown in this paper should be of interest to scholars and policymakers interested in addressing the challenges associated with the APS nexus.

Dermatopathology resident training and education during the COVID-19 pandemic: Challenges faced and lessons learned

Clinical laboratory services and associated training programs faced unprecedented challenges during the coronavirus disease 2019 pandemic. With the introduction of pandemic related strictly mandated institutional policies of physical distancing, dermatopathology rotations, a key component of both dermatology and pathology residency programs, were impacted. In order to adapt to this new environment, a few modifications in resident training and education were introduced at various institutions. These disruptions initiated a change in the standard teaching approach, with a shift from face-to-face learning to a virtual and online model. These adaptations and innovations are discussed here with their likely benefits and limitations.

Calciphylaxis: how specific are the pathological features: avoiding false-positives and false-negatives

Calciphylaxis is considered a critical inflammatory dermatosis with potentially devastating clinical consequences. Skin biopsies are expedited for evaluation and are often considered as a gold standard for diagnostic confirmation and exclusion of other conditions. The key histopathological features include a combination of vascular and extra-vascular calcifications, intravascular microthrombi, and changes related to resulting ischemia. The pathological diagnosis of calciphylaxis is not always a straightforward process as it can be influenced by a number of factors. The specificity of pathological diagnosis of calciphylaxis has been questioned and a systematic approach with multidisciplinary collaboration is required to avoid potential errors.

Nonosseous Periocular Manifestations of Langerhans Cell Histiocytosis: A Case Report and Systematic Review

PURPOSE

Langerhans cell histiocytosis (LCH) is a disorder of dendritic cell proliferation that typically involves bone. It can be diagnostically challenging when LCH presents without bony involvement, leading to delays in diagnosis and treatment. In this study, the periocular manifestations of LCH in cases where the underlying orbital bones are not involved are described through a systematic review.

METHODS

A systematic review of the literature was performed to capture all cases of LCH that involved the periocular region but not the underlying orbital bones. These included LCH cases that involved the periocular skin, the ocular surface, and the orbital tissue. The authors also highlight an additional case where LCH presented with periocular edema and multifocal, nodular conjunctival lesions.

RESULT

This review illustrates that LCH rarely presents with periocular infiltration without orbital bone involvement. In these atypical cases, LCH can present as an eyelid mass, a chalazion-like lesion, generalized periocular swelling, ocular surface lesions, or infiltration of any orbital structure. Ocular surface LCH has a higher rate of recurrence than other periocular LCH. Orbital LCH can involve any tissue including extraocular muscles, the lacrimal gland, or indistinct areas within the orbit.

CONCLUSIONS

LCH is a clinicopathologic diagnosis. Although most cases involve the bone, any soft tissue can be involved. Biopsy is required to confirm the diagnosis of this heterogeneous disease.

Histopathological features of iatrogenic occlusive vasculopathy caused by intra-articular hyaluronic acid injection for osteoarthritis

Occlusive vasculopathy may rarely occur after intra-articular injection with hyaluronic acid. The associated histological changes are not well described. Herein, we would like to present representative histology of this phenomenon.

Muffin Technique Micrographic Surgery for Non-melanoma Skin Cancer

Background: Mohs micrographic surgery (MMS) is the gold standard treatment for high-risk facial non-melanoma skin cancer. However, patients' access to MMS is limited by cost. The muffin technique micrographic surgery (MTMS) is an alternative micrographic technique wherein the entire excised margin is evaluated post-operatively by a pathologist using paraffin-embedded material. Herein, we describe the implementation and the preliminary results of MTMS in an academic dermatology center.

Objective: To describe the MTMS and outline its efficacy and safety in a real-world clinical academic setting.

Methods: A retrospective chart review was conducted of all patients with basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) who underwent MTMS at the University of Alberta Dermatology Center from June 2016 until July 2019.

Results: A total of 69 patients were included (64 BCCs and 5 SCCs). 68.1% of surgeries had clear margins following the first incision, 100% after second round re-excisions. There were no observed cases of tumor recurrence after a median 40 months of follow-up. There were no major adverse events or complications.

Conclusions: MTMS is a superior alternative to simple excision of skin cancer by providing full margin control and residual tumor mapping.

Diagnostic and treatment challenges of a case of primary cutaneous signet-ring cell/histiocytoid carcinoma of the eyelid

Background

Primary cutaneous signet-ring cell/histiocytoid carcinoma of the eyelid is an extremely rare but aggressive neoplasm diagnosed primarily in elderly men. Until now there are 32 published cases of signet-ring cell carcinoma or histiocytoid carcinoma of the eyelid. We report the clinical, radiographic and histological features of the 33rd reported case of PCSRCC in the eyelid of a 73-year-old male, and review diagnostic and treatment challenges of this rare entity.

Case presentation

Our case highlights a 73-year-old male who was referred for surgical correction of right eye ptosis that was present for 2 years. Upon assessment, he was noted to have an upper lateral orbital rim mass. Computed tomography (CT) noted ill-defined soft tissue thickening anterior to the right globe, predominantly pre-septal but with slight post-septal extension. The pathology revealed diffusely and deeply infiltrating tumour cells extending through the dermis, subcutis, orbicularis muscle bundles and nerve fibers; the tumour cells were noted to have a monotonous histiocytoid appearance with foamy granular eosinophilic cytoplasm. At high magnification, intracytoplasmic vacuoles and occasional intermixed signet ring cells were identified. Immunohistochemical staining revealed the tumour cells to be AE1/AE3, CK7, GCDFP-15, E-cadherin, androgen receptor stain and GATA3 positive. Final pathology report confirmed the diagnosis of primary cutaneous signet-ring cell/histiocytoid carcinoma. Further imaging failed to identify a distant primary malignancy or metastatic disease. The decision was made to attempt surgical excision of the tumor. After the bulk of the grossly apparent tumor was removed, intraoperative frozen sections were sent. Superficial biopsies of the right periorbital region were performed, which revealed extension significantly further than the gross disease. Thereafter, the patient underwent a wide orbital exenteration with reconstruction using a temporary split-thickness skin graft. Due to positive margins on final permanent sections, the patient underwent further wide resection with free muscle-skin flap reconstruction followed by adjuvant radiation treatment.

Conclusion

Our case represents the 33rd case of primary signet-ring cell/histiocytoid carcinoma of the eyelid in a 73-year-old male, the first documented case with GATA3 positivity and the second documented case with androgen receptor stain positivity.

A diagnosis of Stevens-Johnson Syndrome (SJS) in a patient presenting with superficial keratitis

Purpose

To describe a case of Stevens-Johnson syndrome (SJS) diagnosed in a patient presenting with primarily ocular findings where SJS had not been initially suspected.

Observations

A 23-year-old female presented with a 2 day history of bilateral eye pain, conjunctival injection, decreased visual acuity, and photophobia in the context of a 4 day history of fever, headache, and sore throat. She was found to have bilateral superficial keratitis and treated for suspected early infectious keratitis secondary to extended contact lens wear. She returned the next day with worsening visual symptoms, a new macular rash over her upper torso, and new ulcerating lesions over her buccal and perioral tissue. The patient was diagnosed with SJS. She was successfully treated using systemic cyclosporine with antibiotics and steroid eye drops.

Conclusions and importance

Ophthalmologists may be the first physicians to diagnose SJS, a life-threatening condition that can initially present with non-specific viral prodromal symptoms and ocular signs alone. This case emphasizes the importance of considering a patient's entire clinical history, especially when the presentation is atypical and the diagnosis is not obviously apparent.

Clinical and Dermoscopic Features of Pigmented Disseminated Superficial Actinic Porokeratosis: Case Report and Literature Review

INTRODUCTION

Porokeratosis is a benign hyperkeratotic skin tumour due to a clonal proliferation of keratinocytes and is characterised by a telltale annular threadlike configuration along the border of a skin-colored to erythematous papule that can expand centrifugally.

CASE PRESENTATION

We are presenting a clinical and dermoscopic case of pigmented disseminated superficial actinic porokeratosis (DSAP) limited to the upper trunk of a white man with sun-damaged skin. Literature Review and Conclusion: A thorough review of PubMed failed to identify any previous reports on the dermoscopic appearance of pigmented porokeratosis. On dermoscopy, the presence of black dots limited to the periphery of the lesions is due to pigment incontinence and melanophages within the superficial papillary dermis limited to the area below the cornoid lamella. Pigmented DSAP is a unique morphological presentation of porokeratosis, and it is essential to be familiar with its clinical and dermoscopic presentation.

Concomitant B Hairy Cell Leukemia and Mycosis Fungoides in an Elderly Man

The development of both a T- and B-cell lymphoproliferative disorder in one patient is an unlikely coincidence due to the low prevalence of each malignancy. We report a 65-year-old man with a previously documented history of B hairy cell leukemia, who presented with a new-onset acneiform eruption of his scalp, face, trunk, back, and extremities. Routine pathology of the skin lesions with immunohistochemical stains and molecular studies were consistent with a folliculotropic mycosis fungoides. B hairy cell leukemia and mycosis fungoides occurring in the same patient seems to be a rare phenomenon with only 5 cases reported in the literature.

Spontaneous Regression of a Congenital Melanocytic Nevus by Sclerosis

Congenital melanocytic nevi (CMNs) naturally evolve throughout life, growing proportionately with the child, darkening, and exhibiting textural or surface changes (e.g., papillomatous, verrucous, cerebriform), hypertrichosis, and, later in life, lightening of pigmentation. We report the case of a 5-year-old child with complete resolution of a medium-sized CMN involving the distal left leg and foot via sclerosis and in the absence of any halo phenomenon. Spontaneous regression of CMN via sclerosis is rare, and it is thought that an immunologic mechanism different from the mechanism that the halo phenomenon induces mediates this regression. We reviewed the literature on this phenomenon and discuss how it might lead to regression of the nevus.

IgA Cutaneous Purpura Post-Renal Transplantation in a Patient With Long-Standing IgA Nephropathy: Case Report and Literature Review

BACKGROUND

IgA vasculitis is a small-vessel vasculitis caused by deposition of IgA antibodies in tissues. IgA nephropathy and IgAV have long been considered related conditions.

OBJECTIVE

To assess the prevalence and implications of new-onset Henoch-Schönlein purpura (HSP) after renal transplant in patients with underlying IgA nephropathy.

METHODS

The PubMed database was searched for keywords such as IgAV, IgA vasculitis, Henoch-Schönlein purpura, HSP, IgA nephropathy, and renal transplant.

RESULTS

Two cases of new-onset IgA vasculitis post-renal transplant after stopping the prednisone or receiving seasonal influenza vaccine have been reported. We report the case of new-onset IgA cutaneous vasculitis in a renal transplant patient with IgA nephropathy after reduction in his prednisone dosage.

CONCLUSION

The new development of cutaneous IgA vasculitis is unusual in renal transplant patients with IgA nephropathy. Despite these patients' being immunosuppressed, the presence of IgA vasculitis could signal the recurrence of IgA nephropathy.

A Clinicopathologic Review of a Case Series of Dermatofibrosarcoma Protuberans with Fibrosarcomatous Differentiation

Background:

Dermatofibrosarcoma protuberans with fibrosarcomatous differentiation (DFSP-FS) is a rare variant of DFSP with a more aggressive clinical course, characterized by higher rates of local recurrence, metastasis, and death.

Methods:

We conducted a clinicopathologic review of all DFSP-FS cases that occurred in Alberta, Canada, from 1997 to 2007.

Results:

Of the 75 DFSP cases reviewed, 4 demonstrated fibrosarcomatous differentiation. Three patients were female and one was male, and the age range was 25 to 76 years. Three tumors invaded to skeletal muscle, whereas one invaded to subcutaneous tissue only. Although perineural invasion was noted in all four cases, none exhibited lymphovascular space invasion. One local recurrence developed, and two of four tumors metastasized. Metastasis was associated with tumor size, tumor necrosis, grenz zone involvement, ulceration, thickness, and tumor grade. One patient died within 5 years of diagnosis.

Conclusion:

DFSP-FS represents a more aggressive subtype of DFSP. Several features of DFSP-FS may impart a higher risk of metastasis.

Fatal Case of Vulvar Pyoderma Gangrenosum with Pulmonary Involvement: Case Presentation and Literature Review

Introduction:

We report a case of a 61-year-old woman with locally destructive vulvar pyoderma gangrenosum (PG) with pulmonary involvement who was refractory to numerous systemic therapies and developed complications resulting in her demise.

Objective:

To report a rare case of treatment-resistant vulvar PG with pulmonary involvement that proved to be fatal.

Methods:

PubMed was used to search for other reports that discuss PG, or more specifically perigenital PG, with pulmonary involvement.

Results and Conclusion:

A thorough review of the literature revealed 33 cases of PG with pulmonary involvement, with only 4 involving the perigenital region. We report the second case of a female with vulvar PG and pulmonary involvement. In contrast to the first case described, our patient did not respond to systemic therapy, and, ultimately, her disease was fatal. It is hoped that with continued documentation of this rare and potentially lethal presentation of PG, physicians will determine more effective treatments.

Sweet syndrome with panniculitis, arthralgia, episcleritis, and neurologic involvement precipitated by antibiotics

BACKGROUND

Sweet syndrome is an uncommon skin condition, often idiopathic in origin although it may be reactive to various systemic conditions, recent infections, underlying malignancies, and medications.

OBJECTIVE & METHOD

To present a case highlighting a rare clinical presentation and to review the causes of Sweet syndrome with an emphasis on drug-induced etiologies.

RESULTS

We describe a 45-year-old woman who developed Sweet syndrome while receiving nitrofurantoin and ciprofloxacin for a urinary tract infection. Her course of disease was complicated by arthralgias, episcleritis, headaches, and erythema nodosum-like subcutaneous involvement. There was marked improvement with discontinuation of the inciting antibiotics and initiation of systemic steroids.

CONCLUSION

This case illustrates Sweet syndrome related to nitrofurantoin and/or ciprofloxacin. This is the second report of Sweet syndrome related to these antibiotics and the first associated with ocular, joint, and neurologic involvement.

Primary systemic (amyloid light-chain) amyloidosis masquerading as pseudoxanthoma elasticum: recognizing a novel clinicopathological pattern

IMPORTANCE

Primary systemic (amyloid light-chain [AL]) amyloidosis has a variety of cutaneous manifestations. In this case, we present a novel clinicopathological pattern of AL amyloidosis.

OBSERVATIONS

A woman in her 50s with a history of AL amyloidosis manifesting as macroglossia and bilateral carpal tunnel syndrome presented with skin-colored to yellow cobblestoned plaques to the neck and bilateral antecubital fossa. Although clinical similar to pseudoxanthoma elasticum (PXE), the skin changes were found to be due to amyloid deposition primarily around the pilosebaceous unit but also within the papillary and reticular dermis. Previous reports of PXE-like plaques in AL amyloidosis have been reported as part of a very rare entity termed amyloid elastosis. However, our case demonstrates several important clinical and pathological differences from this entity. Most notably, there was no dermal elastic fiber involvement, limited cutaneous and systemic involvement, and a fairly indolent course with better response to treatment.

CONCLUSIONS AND RELEVANCE

Identification of this atypical presentation of AL amyloidosis has important implications for early detection and rapid treatment. The lack of elastic fiber involvement establishes the uniqueness of this case, and further study may be required to determine if this histological finding has prognostic significance.

Eruptive Melanocytic Nevi Induced by Interferon for Nodal Metastatic Melanoma: Case Report and Review of the Literature

Background:

The rapid appearance of multiple new melanocytic nevi is known as eruptive nevi and has been well documented to occur with certain medications, in particular chemotherapeutic agents.

Methods:

We report a case of a woman with melanoma complicated by nodal metastasis who developed multiple melanocytic nevi while on high-dose interferon.

Results:

Serial photographs confirmed that the pigmented lesions were of new onset, whereas histology documented that the lesions were dysplastic nevi. A survey of the literature documented numerous causes of eruptive nevi, which we review. To date, interferon has not been linked to eruptive nevi.

Conclusions:

The phenomenon of eruptive nevi has been attributed to medications, bullous dermatoses, immunosuppression, and systemic conditions and is possibly a paraneoplastic disorder. Interferon appears to be another possible cause of this disorder.

Erythema induratum: case series illustrating the utility of the interferon-γ release assay in determining the association with tuberculosis

BACKGROUND

The interferon-γ release assay (IGRA) is a novel method for detecting previous sensitization to tuberculosis (TB). Despite having several advantages over the tuberculin skin test (TST), including higher specificity and no influence from past bacille Calmette-Guérin (BCG) exposure, there are a limited number of reports describing its application in patients with erythema induratum (EI)/nodular vasculitis (NV), which is usually but not always related to TB.

OBJECTIVES

The aim of our case series was to evaluate the usefulness of the IGRA for determining a TB association in patients with EI/NV.

METHODS

Retrospective chart reviews were conducted on four patients diagnosed with EI/NV at our institution in whom an IGRA had been performed.

RESULTS

All four subjects had positive TST results. The IGRA was also positive and therefore supported a link with TB in two cases. One patient responded completely to anti-TB therapy, whereas the second was lost to follow-up. Both cases unrelated to TB, by virtue of negative IGRAs, demonstrated complete response to immunosuppressive therapy (methotrexate), with one individual having failed anti-TB therapy first.

CONCLUSION

Our case series highlights the utility of the IGRA for establishing a TB association in patients with EI/NV. Although limited by a small sample size, we propose adjunctive use of this test at the time of EI/NV diagnosis, especially in the setting of previous BCG exposure, so that management can be tailored according to whether an underlying relationship with TB exists.

Platelet function testing to assess effectiveness of platelet transfusion therapy

BACKGROUND

Posttransfusion corrected count increments (CCI) following administration of platelets is the standard method for assessing effectiveness of platelet transfusion therapy. However, improvement in platelet count following transfusion may not necessarily indicate improvement in platelet function or restoration of primary hemostatic capacity. To address this possibility, we investigated the effectiveness of platelet transfusion based on results of the Platelet Function Analyzer (PFA-100) and post-transfusion CCI. INVESTIGATION DESIGN AND METHODS: Platelet transfusion requests with different indications received at the blood bank were evaluated for inclusion in the investigation. Pre-transfusion, the following laboratory tests were performed: (1) PFA-100 assays (blood collected in 3.2% buffered sodium citrate) performed with CEPI and CADP test cartridges; (2) complete blood count (in EDTA) and platelet count; and (3) routine coagulation profile including PT, PTT, fibrinogen and D-Dimer. Only patients with normal coagulation profiles were included. The same set of tests were performed on a new blood sample collected 10-60 min post-transfusion. Chart review and clinical evaluation for response to platelet therapy were performed on each occasion of transfusion.

RESULTS

Thirty-one patients, five of whom were transfused on more than one occasion were evaluated. Thirty-five transfusion incidents were included. Posttransfusion outcomes were divided into two groups--those that resulted in shortening (>40 s) or normalization of the closure time (Group A) and those that had no change or greater prolongation of the closure time (Group B) when compared to the pre-transfusion value. Seventeen and eighteen transfusion episodes were categorized as Groups A and B, respectively. In Group A with improved PFA testing, nine patients had bleeding as indication for transfusion and six of these had concomitant improvement in their clinical picture as confirmed by control of hemorrhage. In contrast in Group B with no improvement in PFA testing, seven patients had bleeding as indication for transfusion and none showed cessation of hemorrhagic symptoms. These findings were statistically significant (p=0.0114). Similar evaluation using the post-transfusion CCI showed no correlation to bleeding symptoms in these patients (p-=0.500).

CONCLUSIONS

In this evaluation, platelet function testing using the PFA-100 provided a better indication of transfusion outcome than did the post-transfusion CCI. Using this approach, PFA-100 may be an effective aid for supporting platelet transfusion decisions and may further aid in improving management of the hospital blood bank platelet inventory.

p16INK4a expression in actinic keratosis and Bowen's disease

BACKGROUND

Progression of cutaneous squamous neoplasms from actinic keratosis (AK) to Bowen's disease (BD; squamous cell carcinoma in situ) has important implications for clinical management and treatment, thus requiring accurate diagnosis. p16INK4a is a cell cycle regulatory tumour suppressor protein that negatively regulates D-type cyclins in the G1 cell cycle phase via intimate interplay with the retinoblastoma gene. Expression of a paraffin-reactive p16INK4a marker has recently been shown to increase in cervical squamous neoplasms as lesions progress from low-grade dysplasia to squamous cell carcinoma in situ. p16INK4a expression in the progression of squamous cutaneous neoplasia, however, has not been evaluated.

OBJECTIVES

To evaluate p16INK4a expression in the progression of squamous cutaneous neoplasia.

METHODS

Biopsies of 203 squamous cutaneous neoplasms with unequivocal features of AK (n = 87) and BD (n = 116) as well as a benign squamous control group (verruca vulgaris: n = 10; seborrhoeic keratosis: n = 11; scar tissue: n = 8) obtained between January and December 2001 at Henry Ford Hospital (Detroit, MI, U.S.A.) were immunostained for p16INK4a (Dako; clone E6H4; dilution 1 : 50) using large core (1.5 mm) tissue microarray analysis. Nuclear/cytoplasmic immunoreactivity in > 10% of neoplastic cells was considered positive.

RESULTS

Of 203 cases, 166 (81.8%) were interpretable (AK 59; BD 107). Mean patient age was 71.0 years (range 33-93); 57% were male. Sites of involvement were: head and extremities 75.9%, trunk/buttocks 21.7%, genital region 2.4%. p16INK4a immunostaining was positive in 90 of 107 (84.1%) BD cases, four of 59 (6.8%) AK cases and none of 29 benign squamous controls. The sensitivity and specificity of p16INK4a for a diagnosis of BD (vs. benign squamous controls/AK) was 84.1% and 95.5%, respectively (P < 0.0001, Fisher's exact test, two-sided).

CONCLUSIONS

p16INK4a is a sensitive and specific marker for distinguishing BD from AK/benign squamous cutaneous lesions and may be helpful as an adjunct to histomorphology in the diagnosis and appropriate clinical management of these lesions.

Solitary sclerotic fibroma of skin: a possible link with pleomorphic fibroma with immunophenotypic expression for O13 (CD99) and CD34

BACKGROUND

Solitary sclerotic fibroma (SF) presents as a well circumscribed dermal nodule, composed of sparse spindle cells with alternating wavy collagen fibers arranged in a storiform pattern. The histogenesis and nature of this histologically distinct lesion are uncertain. Whether this peculiar tumor represents a true hamartoma or a degenerating end of various fibrous lesions such as pleomorphic fibroma (PF), dermatofibroma, or angiofibroma is still controversial. High proliferating index of spindle cells in SF argues against the possibility of being a degenerating end product of another lesion.

METHODS

We studied morphological features and immunoprofile of eight SFs, in comparison with four PFs, one collagenized dermatofibroma, two angiofibromas, and two periungual fibromas. Immunostains for CD34, CD31, O13 (CD99), Factor XIIIa, S-100, CD68 (KP-1), and MIB-1 were carried out using a labeled streptavidin-biotin method with DAKO-automated immunostainer. Paraffin blocks of two SFs were reprocessed for electron microscopic studies. Clinical data of all patients with SF were also reviewed.

RESULTS

Spindle cells and pleomorphic cells in SF and PF showed diffuse immunoreactivity for CD34 and O13 but were negative for CD31, S-100, and CD68. Spindle cells in one dermatofibroma and one angiofibroma were positive for Factor XIIIa. Proliferating index (MIB-1) was very low in all cases of SF, contradicting some previous reports.

CONCLUSIONS

SF is a fibrotic lesion with cells positive for CD34 and O13. It shares a common immunoprofile with PF but is distinct from dermatofibroma and other common spindle cell lesions of skin. O13 expression in SF has not been previously described.

Diagnostic value of HMB-45 and anti-Melan A staining of sentinel lymph nodes with isolated positive cells

Numerous immunohistochemical stains have been employed to detect metastatic melanoma in sentinel lymph node (SLN) biopsies. HMB-45 is considered by some as a specific tool to detect early metastatic melanoma (1). Occasionally, one or two isolated HMB-45-positive cells may cause complications in diagnostic interpretation. The goal of this study was to evaluate the reliability of HMB-45 staining of SLNs with sparse isolated positive cells and to compare its staining with anti-Melan A antibody. HMB-45 and anti-Melan A antibody immunostaining was performed on (Group A) 15 histologically negative SLNs excised from patients with malignant melanoma (MM) and on (Group B) 15 histologically negative SLNs excised from patients with breast carcinoma (BC). None of the patients had clinical evidence of systemic metastasis at the time of SLN biopsy. Five cutaneous biopsies with changes of postinflammatory hyperpigmentation (PIHP) were also stained with both antibodies. HMB-45 staining was repeated in all Group B SLNs after blocking endogenous biotins. Electron-microscopic studies were performed on all cases of PIHP. Isolated HMB-45-stained cells were present in 6 of 15 SLNs removed for MM; 8 of 15 for BC; and 3 of 5 cutaneous biopsies of PIHP. HMB-45 reactivity persisted after blocking endogenous biotins in 6 of 8 positive SLNs from Group B. Anti-Melan A antibody was negative in all SLNs of group A and B and in dermal melanophages of all five cases of PIHP. HMB-45 positivity was demonstrated in histologically negative SLNs and cutaneous biopsies, especially in the milieu of aggregated melanophages. Phagocytosis of premelanosomes by macrophages in the draining lymph nodes may account for isolated cell positivity and can hinder correct diagnostic interpretation. HMB-45 may not be a reliable marker for the detection of micro-metastasis of MM and requires correlation with other immunohistochemical markers, such as anti-Melan A antibody, to enhance specificity.