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abdomen for 9 years with recent slow growth (Figure 1). She presented with a 5.0- · 3.0-cm verrucous plaque with complaints of itching and bleeding. Biopsy revealed an atypical poroid neoplasm with mitotic and apoptotic activity and ductal differentiation consistent with porocarcinoma in situ (Figure 1). The tumor was cleared with 2 stages of Mohs surgery. The debulk specimen was sectioned and did not contain any evidence of invasive disease. The lymph node examination was normal, and the patient has had no recurrence of the tumor after 12 months of follow-up. This case is similar to that presented by Kohli and colleagues and further reinforces both the index of suspicion needed for biopsy of these lesions and the effectiveness of Mohs surgery for treating these lesions. Ultimately, as dermatologic surgeons, we are attempting to treat carcinomas at early stages to prevent invasive disease and extensive locoregional spread. Not much literature exists regarding treatment of porocarcinomas with Mohs surgery,8,9 and in these small series, Mohs surgery seems to have been successful in treating local disease. Invasive porocarcinoma in the largest series of 54 patients with follow-up2 had 9 (17%) develop local recurrence, 10 (19%) develop nodal disease, and 6 (11%) develop distant metastases or death. A case of metastatic disease after Mohs surgery has been reported,10 with metastatic disease occurring 2 years after initial clear margins by Mohs surgery. This case serves as a reminder of the potential for these tumors to cause significant morbidity and mortality. As the author says to his residents, “Always respect the squamous cell carcinoma.” The same can be said for rare forms of skin cancer such as
porocarcinoma, which given time, can also be destructive and potentially deadly.
References 1. Kohli N, Soohyun Kim S, Brian Jiang SI. Malignant hidroacanthoma simplex treated with Mohs surgery. Dermatol Surg 2015;41:518–520. 2. Mehregan AH, Hashimoto K, Rahbari H. Eccrine adenocarcinoma. A clinicopathologic study of 35 cases. Arch Dermatol 1983;119:104–14. 3. Robson A, Greene J, Ansari N, et al. Eccrine porocarcinoma (malignant eccrine poroma): a clinicopathologic study of 69 cases. Am J Surg Pathol 2001;25:710–20. 4. Bardach H. Hidroacanthoma simplex with in situ porocarcinoma. A case suggesting malignant transformation. J Cutan Pathol 1978;5:236–48. 5. Anzai S, Arakawa S, Fujiwara S, Yokoyama S. Hidroacanthoma simplex: a case report and analysis of 70 Japanese cases. Dermatology 2005;210:363–5. 6. Lee JB, Oh CK, Jang HS, Kim MB, Jang BS, Kwon KS. A case of porocarcinoma from pre-existing hidroacanthoma simplex: need of early excision for hidroacanthoma simplex? Dermatol Surg 2003;29:772–4. 7. Wen SY. Case report of eccrine porocarcinoma in situ associated with eccrine poroma on the forehead. J Dermatol 2012; 39:649–51. 8. Wittenberg GP, Robertson DB, Solomon AR, Washington CV. Eccrine porocarcinoma treated with Mohs micrographic surgery: a report of five cases. Dermatol Surg 1999;25:911–3. 9. McMichael AJ, Gay J. Malignant eccrine poroma in an elderly AfricanAmerican woman. Dermatol Surg 1999;25:733–5. 10. Vleugels FR, Girouard SD, Schmults CD, et al. Metastatic eccrine porocarcinoma after Mohs micrographic surgery: a case report. J Clin Oncol 2012;30:e188–91.
Keith Duffy, MD Department of Dermatology and Huntsman Cancer Institute University of Utah Salt Lake City, Utah The authors have indicated no significant interest with commercial supporters.
Imaging of Desmoplastic Trichoepithelioma by High-Definition Optical Coherence Tomography Desmoplastic trichoepithelioma (DTE) is a rare benign adnexal tumor with follicular differentiation that appears most frequently on the face of young women. It can clinically mimic a variety of skin tumors such as intradermal nevus, sebaceous hyperplasia, and basal cell carcinoma (BCC).1 Because of its overlapping clinical features, the diagnosis of DTE is usually established on histopathology. However, given the
522
predilection of DTE on cosmetically sensitive areas on the face, the indication for biopsy should be as accurate as possible. Several noninvasive imaging techniques have emerged in recent years, aiming for higher accuracy of in vivo diagnosis. These include dermoscopy, reflectance confocal microscopy (RCM), and conventional optical coherence tomography (OCT). High-definition (HD) OCT (Skintell; Agfa
DERMATOLOGIC SURGERY
© 2015 by the American Society for Dermatologic Surgery, Inc. Published by Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
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through a grayscale or color palette resulting in an OCT image. High-definition OCT is capable of capturing not only slice but also en face images in real time and fast 3-dimensional acquisition. Therefore, HD-OCT allows in vivo examination of the skin, enabling visualization of individual cells with a greater depth than RCM. It also provides cross-sectional imaging like the conventional OCT. Additional technical details are discussed elsewhere.2
Figure 1. Dermoscopy of the skin-colored papule located on the right cheek showed multiple fine arborizing vessels (black arrows) on a white-ivory background (black asterisk) and also few white clods probably corresponding to horn cysts (black arrowheads). There were no leaf-like structures, ovoid nests, or shiny-white streaks.
HealthCare, Brussels, Belgium) is a recently introduced technique based on the same principles of conventional OCT but differing on its ability to give optical imaging up to 570 mm deep within the skin, with high resolution of 3 mm both in axial and lateral directions. The field of view is 1.8 · 1.5 mm, and the total light power at the tissue is less than 3.5 mW. The system works in direct contact with the skin. The interference signal detected by the 2-dimensional imaging sensor is digitized, subsequently transferred to a computer, and displayed
As an example of its potential as an accurate in vivo noninvasive diagnostic technique revealing new cytomorphological details, the authors report a 24-year-old woman who presented to the clinic with a 1-year history of an asymptomatic slow-growing papule located on her right cheek. The physical examination revealed a solitary, firm, skin-colored papule, 4 mm in maximum diameter, with a raised annular border and slightly depressed in the center. Dermoscopy disclosed sharply focused fine arborizing vessels, mostly at the periphery, on a white-ivory background. Few white clods probably corresponding to horn cysts were also observed (Figure 1). The clinical and dermoscopic features were suggestive of morpheaform BCC versus DTE. The lesion was further examined by RCM and HD-OCT. Reflectance confocal microscopy revealed
Figure 2. (A) Reflectance confocal microscopy (basic image, 0.5 · 0.5 mm) in the superficial dermis showed multiple dark, round, or elongated tumor islands in the superficial dermis (red arrow); within some of these islands, round small spaces were filled with highly refractile material corresponding to early horn cysts (white asterisk); tumor islands were surrounded by brightly refractile collagen arranged in parallel bundles (red asterisk). (B) Reflectance confocal microscopy (basic image, 0.5 · 0.5 mm) also disclosed larger, ovoid, highly refractile structures within some islands, probably representing focus of tumor calcification (red arrow); and dilated vessels (yellow arrow).
41:4:APRIL 2015
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© 2015 by the American Society for Dermatologic Surgery, Inc. Published by Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
LETTERS AND COMMUNICATIONS
Figure 3. (A) High-definition OCT slice imaging revealed multiple low-refractile aggregates of tumor cells in the dermis (white arrow), variable stroma reaction (red arrows), and normal epidermal architecture. (B and C) High-definition OCT en face imaging also enabled the observation of round to elongated low-reflective tumor islands in the dermis (white asterisks) surrounded by highly reflective collagen (black arrowhead) and also dilated vessels (white arrow); some of these islands connected to follicles (red asterisk).
multiple dark mostly elongated tumor islands in the superficial dermis. Within these structures, round small black spaces filled with highly refractile material corresponding to early horn cysts were also seen. The tumor islands were surrounded by brightly refractile collagen arranged in parallel bundles (Figure 2A). Larger, ovoid, highly refractile structures were seen within some islands, representing focus of tumor calcification. Few dilated vessels diffusely distributed in the stroma were observed (Figure 2B). High-definition OCT slice mode enabled the observation of multiple low-refractile aggregates of tumor cells in the dermis together with some dilated blood vessels and variable stroma reaction; architectural disarray of the epidermis was absent (Figure 3A). En face imaging showed mostly elongated low-reflective tumor islands in the dermis surrounded by highly reflective material corresponding to fibrous stroma and also dilated vessels; some of these islands were connected to follicular structures and some were filled by highly reflective material representing tumor calcification; pleomorphism of the overlying epidermis, peritumoral inflammatory cells, or a dark rim
524
surrounding tumor islands were also absent (Figure 3B). Based on these features, the diagnosis of DTE was favored. A biopsy specimen was taken, and the histopathologic examination showed narrow strands of tumor cells
Figure 4. These structures correlated well with histopathologic examination that showed narrow strands of small basaloid cells without atypia in a densely collagenous stroma, confirming the diagnosis of DET; horn cysts and focus of calcification were seen within some of the islands (H&E, original magnification ·40).
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composed of small basaloid cells without atypia in a densely collagenous stroma. Horn cysts and focus of calcification were seen within some of the islands. These features confirmed the diagnosis of DTE (Figure 4A).
Discussion This case not only supports the previously reported dermoscopic, RCM, and histological features of a DTE but also provides novel insights into its morphological features using HD-OCT. The low-reflective dermal tumor islands (slice and en face) correlate with the dark tumor islands seen in RCM and also with the strands of basaloid cells observed in histology.3,4 The surrounding highly reflective collagen and dilated vessels in HD-OCT correspond to the same structures presented in the desmoplastic stroma both in RCM and histopathology. The presence of these features, the connection between some islands and follicles, and also the absence of epidermal disarray, inflammatory cells, and peripheral dark rim, which are usually seen in BCC, allowed to favor the diagnosis of DTE over BCC in HD-OCT.5 In conclusion, this case demonstrated an excellent correlation between HD-OCT, RCM, and histopathology. To the best of the authors’ knowledge, this is the first report of HD-OCT imaging of rare DTE. Recognition of such features may facilitate its in vivo diagnosis, avoiding invasive diagnostic techniques of an otherwise benign tumor frequently located in cosmetically sensitive areas.
References 1. Mamelak AJ, Goldberg LH, Katz TM, Graves JJ, et al. Desmoplastic trichoepithelioma. J Am Acad Dermatol 2010;62:102–6. 2. Boone M, Norrenberg S, Jemec G, Del Marmol V. High-definition optical coherence tomography imaging of melanocytic lesions: a pilot study. Arch Dermatol Res 2014;306:11–26. 3. Khelifa E, Masouyé I, Kaya G, Le Gal FA. Dermoscopy of desmoplastic trichoepithelioma reveals other criteria to distinguish it from basal cell carcinoma. Dermatology 2013;226:101–4. 4. Ardigo M, Zieff J, Scope A, Gill M, et al. Dermoscopic and reflectance confocal microscopy findings of trichoepithelioma. Dermatology 2007; 215:354–8. 5. Boone MALM, Norrenberg S, Jemec GBE, Del Marmol V. Imaging of basal cell carcinoma by high-definition optical coherence tomography: histomorphological correlation. A pilot study. Br J Dermatol 2012;167: 856–64.
André Oliveira, MD Department of Dermatology Hospital de Curry Cabral—Centro Hospitalar de Lisboa Central Lisboa, Portugal Edith Arzberger, MD Iris Zalaudek, MD Rainer Hofmann-Wellenhof, MD Department of Dermatology Medical University of Graz Graz, Austria The authors have indicated no significant interest with commercial supporters.
Preoperative Ultrasound and Photoacoustic Imaging of Nonmelanoma Skin Cancers There is a growing concern over the rising incidence of nonmelanoma skin cancer (NMSC), and higher treatment-related cost may become a burden on the healthcare system. Management of NMSC is usually surgical either by local excision or Mohs micrographic surgery (MMS).1 Tumor recurrence rates, prolonged surgical times, and significant patient morbidity could be improved with tools that would allow for more accurate tumor evaluation and planning before surgery. Several noninvasive imaging modalities have been applied to NMSC. Among them, high-frequency
ultrasound (HFUS) can provide structural information about tumor size with its high resolution (50 mm) and deep penetration depth (>2 mm).1,2 However, the technique relies on mechanical contrast rather than functional contrast. It is desirable to increase tumor contrast for improved tumor demarcation. In this respect, optical contrast can complement ultrasound contrast. Photoacoustic imaging (PAI) can aid HFUS with its high contrast and sensitivity measures. Photoacoustic imaging is based on pulsed laser light being absorbed by chromophores (e.g., hemoglobin in blood), which leads to thermoelastic expansion and generation of sound
41:4:APRIL 2015
525
© 2015 by the American Society for Dermatologic Surgery, Inc. Published by Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
abdomen for 9 years with recent slow growth (Figure 1). She presented with a 5.0- · 3.0-cm verrucous plaque with complaints of itching and bleeding. Biopsy revealed an atypical poroid neoplasm with mitotic and apoptotic activity and ductal differentiation consistent with porocarcinoma in situ (Figure 1). The tumor was cleared with 2 stages of Mohs surgery. The debulk specimen was sectioned and did not contain any evidence of invasive disease. The lymph node examination was normal, and the patient has had no recurrence of the tumor after 12 months of follow-up. This case is similar to that presented by Kohli and colleagues and further reinforces both the index of suspicion needed for biopsy of these lesions and the effectiveness of Mohs surgery for treating these lesions. Ultimately, as dermatologic surgeons, we are attempting to treat carcinomas at early stages to prevent invasive disease and extensive locoregional spread. Not much literature exists regarding treatment of porocarcinomas with Mohs surgery,8,9 and in these small series, Mohs surgery seems to have been successful in treating local disease. Invasive porocarcinoma in the largest series of 54 patients with follow-up2 had 9 (17%) develop local recurrence, 10 (19%) develop nodal disease, and 6 (11%) develop distant metastases or death. A case of metastatic disease after Mohs surgery has been reported,10 with metastatic disease occurring 2 years after initial clear margins by Mohs surgery. This case serves as a reminder of the potential for these tumors to cause significant morbidity and mortality. As the author says to his residents, “Always respect the squamous cell carcinoma.” The same can be said for rare forms of skin cancer such as
porocarcinoma, which given time, can also be destructive and potentially deadly.
References 1. Kohli N, Soohyun Kim S, Brian Jiang SI. Malignant hidroacanthoma simplex treated with Mohs surgery. Dermatol Surg 2015;41:518–520. 2. Mehregan AH, Hashimoto K, Rahbari H. Eccrine adenocarcinoma. A clinicopathologic study of 35 cases. Arch Dermatol 1983;119:104–14. 3. Robson A, Greene J, Ansari N, et al. Eccrine porocarcinoma (malignant eccrine poroma): a clinicopathologic study of 69 cases. Am J Surg Pathol 2001;25:710–20. 4. Bardach H. Hidroacanthoma simplex with in situ porocarcinoma. A case suggesting malignant transformation. J Cutan Pathol 1978;5:236–48. 5. Anzai S, Arakawa S, Fujiwara S, Yokoyama S. Hidroacanthoma simplex: a case report and analysis of 70 Japanese cases. Dermatology 2005;210:363–5. 6. Lee JB, Oh CK, Jang HS, Kim MB, Jang BS, Kwon KS. A case of porocarcinoma from pre-existing hidroacanthoma simplex: need of early excision for hidroacanthoma simplex? Dermatol Surg 2003;29:772–4. 7. Wen SY. Case report of eccrine porocarcinoma in situ associated with eccrine poroma on the forehead. J Dermatol 2012; 39:649–51. 8. Wittenberg GP, Robertson DB, Solomon AR, Washington CV. Eccrine porocarcinoma treated with Mohs micrographic surgery: a report of five cases. Dermatol Surg 1999;25:911–3. 9. McMichael AJ, Gay J. Malignant eccrine poroma in an elderly AfricanAmerican woman. Dermatol Surg 1999;25:733–5. 10. Vleugels FR, Girouard SD, Schmults CD, et al. Metastatic eccrine porocarcinoma after Mohs micrographic surgery: a case report. J Clin Oncol 2012;30:e188–91.
Keith Duffy, MD Department of Dermatology and Huntsman Cancer Institute University of Utah Salt Lake City, Utah The authors have indicated no significant interest with commercial supporters.
Imaging of Desmoplastic Trichoepithelioma by High-Definition Optical Coherence Tomography Desmoplastic trichoepithelioma (DTE) is a rare benign adnexal tumor with follicular differentiation that appears most frequently on the face of young women. It can clinically mimic a variety of skin tumors such as intradermal nevus, sebaceous hyperplasia, and basal cell carcinoma (BCC).1 Because of its overlapping clinical features, the diagnosis of DTE is usually established on histopathology. However, given the
522
predilection of DTE on cosmetically sensitive areas on the face, the indication for biopsy should be as accurate as possible. Several noninvasive imaging techniques have emerged in recent years, aiming for higher accuracy of in vivo diagnosis. These include dermoscopy, reflectance confocal microscopy (RCM), and conventional optical coherence tomography (OCT). High-definition (HD) OCT (Skintell; Agfa
DERMATOLOGIC SURGERY
© 2015 by the American Society for Dermatologic Surgery, Inc. Published by Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
LETTERS AND COMMUNICATIONS
through a grayscale or color palette resulting in an OCT image. High-definition OCT is capable of capturing not only slice but also en face images in real time and fast 3-dimensional acquisition. Therefore, HD-OCT allows in vivo examination of the skin, enabling visualization of individual cells with a greater depth than RCM. It also provides cross-sectional imaging like the conventional OCT. Additional technical details are discussed elsewhere.2
Figure 1. Dermoscopy of the skin-colored papule located on the right cheek showed multiple fine arborizing vessels (black arrows) on a white-ivory background (black asterisk) and also few white clods probably corresponding to horn cysts (black arrowheads). There were no leaf-like structures, ovoid nests, or shiny-white streaks.
HealthCare, Brussels, Belgium) is a recently introduced technique based on the same principles of conventional OCT but differing on its ability to give optical imaging up to 570 mm deep within the skin, with high resolution of 3 mm both in axial and lateral directions. The field of view is 1.8 · 1.5 mm, and the total light power at the tissue is less than 3.5 mW. The system works in direct contact with the skin. The interference signal detected by the 2-dimensional imaging sensor is digitized, subsequently transferred to a computer, and displayed
As an example of its potential as an accurate in vivo noninvasive diagnostic technique revealing new cytomorphological details, the authors report a 24-year-old woman who presented to the clinic with a 1-year history of an asymptomatic slow-growing papule located on her right cheek. The physical examination revealed a solitary, firm, skin-colored papule, 4 mm in maximum diameter, with a raised annular border and slightly depressed in the center. Dermoscopy disclosed sharply focused fine arborizing vessels, mostly at the periphery, on a white-ivory background. Few white clods probably corresponding to horn cysts were also observed (Figure 1). The clinical and dermoscopic features were suggestive of morpheaform BCC versus DTE. The lesion was further examined by RCM and HD-OCT. Reflectance confocal microscopy revealed
Figure 2. (A) Reflectance confocal microscopy (basic image, 0.5 · 0.5 mm) in the superficial dermis showed multiple dark, round, or elongated tumor islands in the superficial dermis (red arrow); within some of these islands, round small spaces were filled with highly refractile material corresponding to early horn cysts (white asterisk); tumor islands were surrounded by brightly refractile collagen arranged in parallel bundles (red asterisk). (B) Reflectance confocal microscopy (basic image, 0.5 · 0.5 mm) also disclosed larger, ovoid, highly refractile structures within some islands, probably representing focus of tumor calcification (red arrow); and dilated vessels (yellow arrow).
41:4:APRIL 2015
523
© 2015 by the American Society for Dermatologic Surgery, Inc. Published by Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
LETTERS AND COMMUNICATIONS
Figure 3. (A) High-definition OCT slice imaging revealed multiple low-refractile aggregates of tumor cells in the dermis (white arrow), variable stroma reaction (red arrows), and normal epidermal architecture. (B and C) High-definition OCT en face imaging also enabled the observation of round to elongated low-reflective tumor islands in the dermis (white asterisks) surrounded by highly reflective collagen (black arrowhead) and also dilated vessels (white arrow); some of these islands connected to follicles (red asterisk).
multiple dark mostly elongated tumor islands in the superficial dermis. Within these structures, round small black spaces filled with highly refractile material corresponding to early horn cysts were also seen. The tumor islands were surrounded by brightly refractile collagen arranged in parallel bundles (Figure 2A). Larger, ovoid, highly refractile structures were seen within some islands, representing focus of tumor calcification. Few dilated vessels diffusely distributed in the stroma were observed (Figure 2B). High-definition OCT slice mode enabled the observation of multiple low-refractile aggregates of tumor cells in the dermis together with some dilated blood vessels and variable stroma reaction; architectural disarray of the epidermis was absent (Figure 3A). En face imaging showed mostly elongated low-reflective tumor islands in the dermis surrounded by highly reflective material corresponding to fibrous stroma and also dilated vessels; some of these islands were connected to follicular structures and some were filled by highly reflective material representing tumor calcification; pleomorphism of the overlying epidermis, peritumoral inflammatory cells, or a dark rim
524
surrounding tumor islands were also absent (Figure 3B). Based on these features, the diagnosis of DTE was favored. A biopsy specimen was taken, and the histopathologic examination showed narrow strands of tumor cells
Figure 4. These structures correlated well with histopathologic examination that showed narrow strands of small basaloid cells without atypia in a densely collagenous stroma, confirming the diagnosis of DET; horn cysts and focus of calcification were seen within some of the islands (H&E, original magnification ·40).
DERMATOLOGIC SURGERY
© 2015 by the American Society for Dermatologic Surgery, Inc. Published by Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
LETTERS AND COMMUNICATIONS
composed of small basaloid cells without atypia in a densely collagenous stroma. Horn cysts and focus of calcification were seen within some of the islands. These features confirmed the diagnosis of DTE (Figure 4A).
Discussion This case not only supports the previously reported dermoscopic, RCM, and histological features of a DTE but also provides novel insights into its morphological features using HD-OCT. The low-reflective dermal tumor islands (slice and en face) correlate with the dark tumor islands seen in RCM and also with the strands of basaloid cells observed in histology.3,4 The surrounding highly reflective collagen and dilated vessels in HD-OCT correspond to the same structures presented in the desmoplastic stroma both in RCM and histopathology. The presence of these features, the connection between some islands and follicles, and also the absence of epidermal disarray, inflammatory cells, and peripheral dark rim, which are usually seen in BCC, allowed to favor the diagnosis of DTE over BCC in HD-OCT.5 In conclusion, this case demonstrated an excellent correlation between HD-OCT, RCM, and histopathology. To the best of the authors’ knowledge, this is the first report of HD-OCT imaging of rare DTE. Recognition of such features may facilitate its in vivo diagnosis, avoiding invasive diagnostic techniques of an otherwise benign tumor frequently located in cosmetically sensitive areas.
References 1. Mamelak AJ, Goldberg LH, Katz TM, Graves JJ, et al. Desmoplastic trichoepithelioma. J Am Acad Dermatol 2010;62:102–6. 2. Boone M, Norrenberg S, Jemec G, Del Marmol V. High-definition optical coherence tomography imaging of melanocytic lesions: a pilot study. Arch Dermatol Res 2014;306:11–26. 3. Khelifa E, Masouyé I, Kaya G, Le Gal FA. Dermoscopy of desmoplastic trichoepithelioma reveals other criteria to distinguish it from basal cell carcinoma. Dermatology 2013;226:101–4. 4. Ardigo M, Zieff J, Scope A, Gill M, et al. Dermoscopic and reflectance confocal microscopy findings of trichoepithelioma. Dermatology 2007; 215:354–8. 5. Boone MALM, Norrenberg S, Jemec GBE, Del Marmol V. Imaging of basal cell carcinoma by high-definition optical coherence tomography: histomorphological correlation. A pilot study. Br J Dermatol 2012;167: 856–64.
André Oliveira, MD Department of Dermatology Hospital de Curry Cabral—Centro Hospitalar de Lisboa Central Lisboa, Portugal Edith Arzberger, MD Iris Zalaudek, MD Rainer Hofmann-Wellenhof, MD Department of Dermatology Medical University of Graz Graz, Austria The authors have indicated no significant interest with commercial supporters.
Preoperative Ultrasound and Photoacoustic Imaging of Nonmelanoma Skin Cancers There is a growing concern over the rising incidence of nonmelanoma skin cancer (NMSC), and higher treatment-related cost may become a burden on the healthcare system. Management of NMSC is usually surgical either by local excision or Mohs micrographic surgery (MMS).1 Tumor recurrence rates, prolonged surgical times, and significant patient morbidity could be improved with tools that would allow for more accurate tumor evaluation and planning before surgery. Several noninvasive imaging modalities have been applied to NMSC. Among them, high-frequency
ultrasound (HFUS) can provide structural information about tumor size with its high resolution (50 mm) and deep penetration depth (>2 mm).1,2 However, the technique relies on mechanical contrast rather than functional contrast. It is desirable to increase tumor contrast for improved tumor demarcation. In this respect, optical contrast can complement ultrasound contrast. Photoacoustic imaging (PAI) can aid HFUS with its high contrast and sensitivity measures. Photoacoustic imaging is based on pulsed laser light being absorbed by chromophores (e.g., hemoglobin in blood), which leads to thermoelastic expansion and generation of sound
41:4:APRIL 2015
525
© 2015 by the American Society for Dermatologic Surgery, Inc. Published by Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
