High-throughput quantitative histology in systemic sclerosis skin disease using computer vision.

BACKGROUND: Skin fibrosis is the clinical hallmark of systemic sclerosis (SSc), where collagen deposition and remodeling of the dermis occur over time. The most widely used outcome measure in SSc clinical trials is the modified Rodnan skin score (mRSS), which is a semi-quantitative assessment of skin stiffness at seventeen body sites. However, the mRSS is confounded by obesity, edema, and high inter-rater variability. In order to develop a new histopathological outcome measure for SSc, we applied a computer vision technology called a deep neural network (DNN) to stained sections of SSc skin. We tested the hypotheses that DNN analysis could reliably assess mRSS and discriminate SSc from normal skin. METHODS: We analyzed biopsies from two independent (primary and secondary) cohorts. One investigator performed mRSS assessments and forearm biopsies, and trichrome-stained biopsy sections were photomicrographed. We used the AlexNet DNN to generate a numerical signature of 4096 quantitative image features (QIFs) for 100 randomly selected dermal image patches/biopsy. In the primary cohort, we used principal components analysis (PCA) to summarize the QIFs into a Biopsy Score for comparison with mRSS. In the secondary cohort, using QIF signatures as the input, we fit a logistic regression model to discriminate between SSc vs. control biopsy, and a linear regression model to estimate mRSS, yielding Diagnostic Scores and Fibrosis Scores, respectively. We determined the correlation between Fibrosis Scores and the published Scleroderma Skin Severity Score (4S) and between Fibrosis Scores and longitudinal changes in mRSS on a per patient basis. RESULTS: In the primary cohort (n = 6, 26 SSc biopsies), Biopsy Scores significantly correlated with mRSS (R = 0.55, p = 0.01). In the secondary cohort (n = 60 SSc and 16 controls, 164 biopsies; divided into 70% training and 30% test sets), the Diagnostic Score was significantly associated with SSc-status (misclassification rate = 1.9% [training], 6.6% [test]), and the Fibrosis Score significantly correlated with mRSS (R = 0.70 [training], 0.55 [test]). The DNN-derived Fibrosis Score significantly correlated with 4S (R = 0.69, p = 3 × 10- 17). CONCLUSIONS: DNN analysis of SSc biopsies is an unbiased, quantitative, and reproducible outcome that is associated with validated SSc outcomes.

Detection of Borrelia in Ixodes scapularis ticks by silver stain, immunohistochemical and direct immunofluorescent methods.

BACKGROUND: Lyme disease (LD) is one of the most common tick-borne diseases caused by several Borrelia species of spirochetes. Ixodes scapularis is responsible for the transmission of LD in the northeastern United States. The rate of infection varies with the duration of tick attachment to the host; however, this information may be unknown. In skin biopsies, it is often difficult to identify spirochetes. Testing of ticks is not routinely performed. Treatment is established by clinical presentation. OBJECTIVE: To test paraffin-embedded I. scapularis ticks for Borrelia by different methods. MATERIALS/METHODS: We examined 20 paraffin-embedded ticks by silver stain, immunohistochemical (IHC) and direct immunofluorescent (DIF) methods and compared the percentage of positivity with DIF results from the Connecticut Agricultural Experiment Station. RESULTS: The results were similar by DIF, which proved to be the most sensitive method, followed by the silver stain and IHC. CONCLUSION: We found that the identification of spirochetes in paraffin-embedded ticks was less difficult than in tissue with a comparable turnaround time to that of a routine biopsy. Timely identification of Borrelia in ticks may influence the clinical management of the patients.

Well-differentiated neuroendocrine tumors in skin: Terminology and diagnostic utility of cytokeratin 5/6 and p63.

BACKGROUND: Well-differentiated neuroendocrine tumors (WDNETs) in skin include metastases from visceral primary sites and very uncommonly, primary cutaneous carcinoid tumors. Cutaneous WDNET may present a diagnostic challenge and in particular can be mistaken for a benign skin adnexal tumor. In contrast to cutaneous adnexal tumors, metastatic adenocarcinomas to the skin are cytokeratin 5/6 (CK5/6) and p63 negative in the majority of cases. It is unclear if failure to stain with CK5/6 and p63 would be helpful in differentiating WDNETs from cutaneous adnexal neoplasms. METHODS: We reviewed 10 cases of cutaneous WDNETs (8 cases of metastatic disease and 2 presumed primary carcinoid tumors of the skin) and performed immunohistochemical stains for CK5/6 and p63 on all cases. RESULTS: All 10 cases were negative with both CK5/6 and p63. CONCLUSION: Negative staining for CK5/6 and p63 can be helpful to distinguish WDNETs from cutaneous adnexal neoplasms. It is important to consider WDNETs in the differential diagnosis of cutaneous adnexal neoplasms as low-grade tumors may be the first sign of aggressive metastatic disease.

Mycosis fungoides exhibiting features of a dermatofibroma: a case report and review of the literature.

We present the case of a 60-year-old male with known stage IA mycosis fungoides (MF) who developed a suspicious tumor within a pre-existing lymphomatous plaque of the right forearm. Microscopy revealed an unusual mixed fibrohistiocytic proliferation as well as atypical intraepidermal and dermal lymphocytes. There was no evidence of large-cell transformation. Histopathological, immunohistochemical and clinical clues suggest this lesion might not have represented a dermatofibroma, but rather a hitherto unreported dermatofibroma-like process arising within a lesion of MF. The potential impact of this atypical lesion on the prognosis and clinical management of this patient highlights the importance of recognizing unusual clinical presentations of more common, benign lesions within this patient population.

Metastatic cutaneous carcinoid tumor mimicking an adnexal poroid neoplasm.

OBJECTIVE: Metastatic cutaneous neoplasms may be difficult to differentiate from primary cutaneous neoplasms. Herein, we report an unusual case of metastatic cutaneous carcinoid tumor mimicking an adnexal poroid neoplasm. METHODS: A 53-year-old male man presented with a neoplasm on the vertex of the scalp, clinically resembling a pigmented basal cell carcinoma. RESULTS: A shave biopsy was suggestive of an apocrine poroma, however, a metastatic carcinoma could not be excluded. After acquiring additional clinical information and the complete excision of the neoplasm, further immunohistochemical stains supported the diagnosis a metastatic carcinoid tumor. CONCLUSION: To our knowledge, this is the first case of metastatic carcinoid tumor reported that has mimicked a poroid neoplasm.

The histopathology of primary cicatricial alopecia.

Alopecia typically is divided into cicatricial (scarring) and noncicatricial (nonscarring) forms. "Scarring" alopecia implies that follicular epithelium has been replaced by connective tissue and is therefore an irreversible process. In contrast, nonscarring alopecia is potentially reversible as follicular epithelia remain intact. Classification of cicatricial alopecia can be confusing and controversial as most disorders demonstrate overlapping clinical and histologic features. Herein, we present an overview of the histologic assessment of cicatricial alopecia, including an algorithmic approach to the evaluation of biopsy specimens from patients with scarring alopecia.

The role of circulating fibrocytes in fibrosis.

Fibrocytes are cells that circulate in the peripheral blood and produce connective tissue proteins such as vimentin and collagens I and III. Fibrocytes are associated with skin lesions, pulmonary fibrosis, and tumors and they contribute to the remodeling response by secreting matrix metalloproteinases. Fibrocytes can further differentiate, and they are a likely source of the contractile myofibroblast that appears in many fibrotic lesions. There is evidence in the skin for a prominent role for fibrocytes in the development of hypertrophic scars and keloids. In asthma or in experimental models of pulmonary fibrosis, fibrocytes have been shown to infiltrate areas of inflammation and tissue damage. Fibrocytes constitute part of the stromal response to tumor invasion, and there is evidence that these cells may be a prognosticator of malignant potential. IL-1, TGF-beta, chemokines, and serum amyloid P modulate the appearance and function of fibrocytes. Fibrocytes themselves produce inflammatory cytokines, growth factors, and chemokines. The intercellular signals that modulate fibrocyte trafficking, proliferation, and differentiation are only partially defined, but a better understanding of these signals enable new therapies to prevent pathologic fibrosis or to improve the tissue repair response.

CD56 staining in Merkel cell carcinoma and natural killer-cell lymphoma: magic bullet, diagnostic pitfall, or both?

BACKGROUND: Antibodies to CD56 label natural killer (NK) cell lymphomas and neuroendocrine tumors such as Merkel cell carcinoma (MCC). In MCC altered by crush artifact or obscured by lymphocytes, the histologic features coupled with CD56 positivity can lead to an erroneous impression of NK-cell lymphoma. METHODS: Eighteen cases of MCC were stained for CD56, CK20, MNF116, and pankeratin. The results were compared to histologic features and CD56 staining pattern of three NK-cell lymphomas. RESULTS: Three of 18 cases of MCC histologically resembled lymphoma, and CD56 positivity with CD3 and CD20 negativity initially raised the possibility of NK-cell lymphoma. Two additional cases were obscured by dense inflammation, again suggesting the diagnosis of lymphoma. Seventeen of 18 MCC labeled for CD56 and an equal number stained for CK20. All MCC tested were positive for CAM5.2 (14/14) and MNF116 (17/17). Antibodies to pankeratin labeled only one of 18 MCC. Staining for CD56 was stronger in MCC than NK-cell lymphomas. CONCLUSIONS: CD56 is a sensitive marker for MCC as well as for NK-cell lymphoma, but is not specific. Importantly, CD56 positivity in crushed or inflamed biopsies of MCC may lead to an erroneous impression of NK lymphoma. Awareness of this potential pitfall will prevent misdiagnosis. McNiff JM, Cowper SE, Lazova R, Subtil A, Glusac EJ. CD56 staining in Merkel cell carcinoma and natural killer-cell lymphoma: Magic bullet, diagnostic pitfall, or both?

Cellular digital fibromas: distinctive CD34-positive lesions that may mimic dermatofibrosarcoma protuberans.

BACKGROUND: Digital fibromas are common benign acral tumors typically reported as angiofibromas (AFs) or acquired digital fibrokeratomas (ADFs). Cellular variants are not well recognized. METHODS: We collected 14 acral fibrocytic lesions showing a spindle cell morphology from our files, and evaluated CD34, Factor XIIIa, epithelial membrane antigen (EMA), and S100 protein staining of these lesions. We compared the histologic and immunohistochemical features of these cellular fibromas with five digital AFs, five ADFs, and five digital dermatofibromas. RESULTS: The 14 cellular digital fibromas showed intersecting fascicles of thin delicate bland spindle cells in the superficial reticular dermis with a fibrotic-to-slight myxoid stroma. The spindle cells in all cases stained strongly for CD34, and only scattered stromal cells stained for Factor XIIIa. Five tested cases were negative for EMA and S100 protein. The digital AFs, fibrokeratomas, and dermatofibromas stained predominately for Factor XIIIa, with no or minimal staining for CD34. CONCLUSIONS: These findings suggest that a subset of digital fibromas is characterized by a dense cellular proliferation of CD34-positive spindle cells. Awareness of this variant of digital fibroma and its staining pattern is critical in preventing misdiagnosis as dermatofibrosarcoma protuberans, particularly in superficial biopsies.

Nephrogenic fibrosing dermopathy: the first 6 years.

PURPOSE OF REVIEW: Nephrogenic fibrosing dermopathy (NFD) is a newly recognized scleroderma-like fibrosing skin condition. It develops in patients with renal insufficiency. This review summarizes recent case reports and examines theories of disease pathogenesis. Information from the Yale University NFD Registry Project, as well as published case reports, is included to provide a contextual framework upon which to base these theories. RECENT FINDINGS: Recent studies have contributed to a clearer definition of the clinical spectrum, epidemiology, and pathogenesis of NFD. The findings of yellow scleral plaques and circulating antiphospholipid antibodies have been proposed as markers of NFD in recent case reports. In addition, epidemiologic data have yielded several distinct clinical patterns of disease onset. Lastly, dual immunohistochemical staining for CD34 and procollagen in the spindle cells of NFD suggest that the dermal cells of NFD may represent circulating fibrocytes recruited to the dermis-a finding previously undescribed in normal skin. SUMMARY: Scenario classification of NFD is a means for simplifying the search for multifactorial disease triggers, and may be helpful in predicting prognosis and response to therapy. The technique of dual immunolabeling, although not yet fully characterized as a diagnostic test, may provide a sensitive and specific method of diagnosis, as well as a starting point in the investigation of other cutaneous fibrosing disorders. The postulate that NFD may represent a systemic disorder mediated by aberrantly functioning circulating fibroblast precursor fibrocytes is explored.

An investigation of apoptosis in androgenetic alopecia.

While the androgens, including dihydrotestosterone (DHT), have been implicated in the development of androgenetic alopecia (AGA), the exact mechanism by which they exert their effects is unknown. As apoptosis is an integral component of the normal cycling of human hair, we investigated individuals clinically affected by AGA to assess whether objective differences in the expression of apoptosis related immunohistochemical markers could be observed in scalp biopsies. Specimens from 13 alopecic male cadavers were stained with bcl-2 and terminal deoxynucleotidetransferase dUTP fluorescein nick end-labeling (TUNEL) methods to assess apoptotic activity in affected and unaffected areas of the scalp. Immunoreactivity was analyzed by quantifying nuclear staining differences within the same individual. Sections from two living human volunteers were obtained to establish the method validity. Significant differences in bcl-2 expression were observed between areas of the scalp clinically affected and unaffected by AGA. The Gaussian distribution of bcl-2 staining suggests that a relatively uniform population of follicles exists at the frontal hairline and/or synchrony of follicular cycling occurs in AGA. The apoptosis "hot spot" described by TUNEL staining in the bulge-isthmus region of the murine follicle is also identifiable in the human follicle.