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Linear atrophoderma of Moulin (LAM) is a rare dermatological condition characterized by unilateral hyperpigmented and atrophic band-like skin lesions following Blaschko's lines. The exact cause of LAM is unclear, but it is believed to be related to either autoimmunity or genetic mosaicism. This article describes a case of LAM in a 27-year-old man, highlighting a granulomatous reaction and antinuclear-antibody (ANA) positivity. The patient's chronic lesions met the diagnostic criteria for LAM, except for a thinner dermis and subcutaneous tissue. The article also discusses the dermoscopic features, treatment options, and the potential link between LAM and autoimmunity or connective tissue diseases. [Extracted from the article]

Linear and whorled nevoid hypermelanosis is a rare skin pigmentation disorder, characterized by linear streaks and whorls of hyperpigmented macules along Blaschko's lines. Lesions are commonly restricted to the trunk, neck, and extremities, sparing the face, palms, soles, and mucosae. Associated with this, certain cardiovascular, musculoskeletal, neurological, and developmental anomalies have been reported in the literature. Herein, we present a rare case of linear and whorled nevoid hypermelanosis involving the face, with musculoskeletal, genital, aural, and ocular abnormalities. [ABSTRACT FROM AUTHOR]

Linear morphea, also known as linear scleroderma, is a localized form of scleroderma characterized by the presence of lesions that follow a linear distribution pattern. Apart from the typical inflammation and fibrosis of the skin, the linear subtype of morphea often affects underlying structures such as muscles and bones, which can lead to functional limitations. Lichen striatus, a linear inflammatory skin condition, primarily affects children aged 5 to 15 years. Interestingly, both diseases can exhibit lesions that follow the lines of Blaschko. Here we report a case with linear morphea following the lines of Blaschko mimicking lichen striatus in a 4‐year‐old child. This unique case represents the first documented instance of linear morphea exhibiting a precise Blaschko pattern and being successfully treated with baricitinib. The patient received oral baricitinib at a daily dosage of 2 mg for a duration of 1 year, resulting in remarkable improvement. The majority of the lesions softened, and there was no significant disease progression or occurrence of adverse events throughout the treatment period. Recognizing linear morphea at an early stage is of utmost importance in ensuring effective treatment and preventing disfiguring sequelae. Patients suspected of lichen striatus should also be closely followed and linear morphea should be excluded during the follow‐up. The recent breakthrough in the application and the safety of baricitinib in scleroderma is also reviewed. [ABSTRACT FROM AUTHOR]

Lichen planus pigmentosus (LPP) is a distinctive variant of lichen planus described for the first time in 1974. A wide range of presentations and distribution patterns have been reported, mainly presenting as dark brown hyperpigmented macules and patches, typically involving sun-exposed areas such as the face, neck, and flexural folds. It is more common in dark-skinned patients with a female predominance. Infrequently, LPP may present as a Blaschkoid distribution, with only a few cases reported in the medical literature. We report an unusual case of LPP that developed with a unilateral Blaschkoid distribution on the left side of the trunk in a 32-year-old female following weight reduction surgery.

Mohammad S Alkhowailed,1 Mojahed Otayf,2 Abdulrahman Albasseet,2 Abdullah Almousa,2 Ziyad Alajlan,2 Saad Altalhab3 1Department of Dermatology, College of Medicine, Qassim University, Buraydah, Qassim, Saudi Arabia; 2College of Medicine, King Saud University, Riyadh, Saudi Arabia; 3Department of Dermatology, College of Medicine, Al-Imam Mohammad Ibn Saud Islamic University, Riyadh, Saudi ArabiaCorrespondence: Mohammad S AlkhowailedDepartment of Dermatology College of Medicine, Qassim University, Buraidah 52571, Qassim, Saudi ArabiaEmail m.alkhowailed@gmail.comAbstract: Linear hyperpigmentation is an unusual anatomical configuration in clinical dermatology. Owing to its rarity, consensus on the most effective method of classification is lacking. While linear hyperpigmentation generally follows Blaschko’s lines, this is not universal. Clinical findings such as adherence to Blaschko’s lines, associated morphological findings (including other cutaneous lesions), and systemic manifestations can be used to further characterize and diagnose variants of the disorder. Early detection of any underlying disease is vital, especially in cases with effective management, because the disorder may make it difficult to manage hyperpigmentation. Herein, we introduce a logical clinical diagnostic approach that represents a useful tool for dermatologists to efficiently evaluate patients presenting with linear hyperpigmentation. A simplified systematic and evidence-based approach is useful for this clinical condition owing to the heterogeneous causes and lack of specific diagnostic tools.Keywords: approach, blaschkitis, Blaschko’s lines, hyperpigmentation, linear, pigmentary mosaicism

ABSTRACT: Background: Inflammatory linear verrucous epidermal nevus (ILVEN) is a rare type of epidermal nevus that occurs in infancy and develops along Blaschko's lines. Due to its rarity and clinical/histological similarities with other cutaneous disorders, correct diagnosis is sometimes difficult. In the present case, the whole exome sequencing of blood found no germline mutation, but the sequencing of the biopsy specimen revealed a novel potential pathogenic somatic mutation, C > T at rs200881715 (p.R698X) in the cspp1 gene, which may provide new insight into the mechanism of ILVEN. Patient concerns: A 10-year-old girl presented with linear, pruritic, erythematous, scaly, and exophytic verrucous skin lesions on her left thigh, buttock, and hand unilaterally along Blaschko's lines from the third day after birth. Diagnosis: Biopsy revealed psoriasiform acanthosis, papillary hyperplasia with orthohyperkeratosis, and parakeratosis of squamous epithelium, which are histological characteristics of ILVEN. Interventions: Owing to the large lesion size and significant refractory response to previous treatments, multiple-stage surgical resections with a tissue expander were performed. Outcomes: After surgical resection and defect reconstruction with a tissue expander, the outcome was satisfactory for the patient and her family. No recurrence was detected during the follow-up visits. Conclusion: ILVEN is a rare type of cutaneous hyperplastic disease, and treatment is extremely challenging. Biopsy should be performed at the diagnostician's discretion or if refractory to conservative treatments. Timely diagnosis and surgical intervention could result in satisfactory outcomes.

Hypomelanosis of Ito is a rare heterogeneous neurocutaneous disorder often associated with central nervous and musculoskeletal system involvement. Herein, we report the first case of hypomelanosis of Ito in the literature presenting with unilateral dilation of Virchow-Robin spaces (VRS). A girl aged 16 years old presented with a 1-year history of headache. Her physical and neurological examinations were normal, except for the presence of unilateral cutaneous macular hypopigmented whorls and streaks on lower side of the right trunk and lower limb, termed as Blaschko's lines. She had mild deficits in cognitive and adaptive functioning. Hearing, renal, dental, ophthalmologic, metabolic, and cardiac assessments were normal. Brain magnetic resonance imaging (MRI) showed markedly unilateral hemispheric enlarged VRS without contrast enhancement and diffusion restriction. To the best of our knowledge, our case is the first report describing the unilateral hemispheric enlarged VRS in a patient with hypomelanosis of Ito. Our report suggested that hypomelanosis of Ito may have unilateral dilation of VRS in brain MRI. [ABSTRACT FROM AUTHOR]

Blaschkitis is an acquired, rare dermatosis distributed along the lines of Blaschko. The papulovesicular eruption generally resolves in weeks and shows minimal response to topical steroids. Herein, we present a case of blaschkitis in an adult male who had lesions present for one year, which showed significant improvement after two weeks of topical clobetasol ointment.

Abstract Background Pigmentary mosaicism is a term that describes varied patterns of pigmentation in the skin caused by genetic heterogeneity of the skin cells. In a substantial number of cases, pigmentary mosaicism is observed alongside extracutaneous abnormalities typically involving the central nervous system and the musculoskeletal system. We have compiled information on previous cases of pigmentary mosaicism aiming to optimize the handling of patients with this condition. Our study is based on a database search in PubMed containing papers written in English, published between January 1985 and April 2017. The search yielded 174 relevant and original articles, detailing a total number of 651 patients. Results Forty-three percent of the patients exhibited hyperpigmentation, 50% exhibited hypopigmentation, and 7% exhibited a combination of hyperpigmentation and hypopigmentation. Fifty-six percent exhibited extracutaneous manifestations. The presence of extracutaneous manifestations in each subgroup varied: 32% in patients with hyperpigmentation, 73% in patients with hypopigmentation, and 83% in patients with combined hyperpigmentation and hypopigmentation. Cytogenetic analyses were performed in 40% of the patients: peripheral blood lymphocytes were analysed in 48%, skin fibroblasts in 5%, and both analyses were performed in 40%. In the remaining 7% the analysed cell type was not specified. Forty-two percent of the tested patients exhibited an abnormal karyotype; 84% of those presented a mosaic state and 16% presented a non-mosaic structural or numerical abnormality. In patients with extracutaneous manifestations, 43% of the cytogenetically tested patients exhibited an abnormal karyotype. In patients without extracutaneous manifestations, 32% of the cytogenetically tested patients exhibited an abnormal karyotype. Conclusion We recommend a uniform parlance when describing the clinical picture of pigmentary mosaicism. Based on the results found in this review, we recommend that patients with pigmentary mosaicism undergo physical examination, highlighting with Wood’s light, and karyotyping from peripheral blood lymphocytes and skin fibroblasts. It is important that both patients with and without extracutaneous manifestations are tested cytogenetically, as the frequency of abnormal karyotype in the two groups seems comparable. According to the results only a minor part of patients, especially those without extracutaneous manifestations, are tested today reflecting a need for change in clinical practice.

Background: Pathogenic mechanism that determines the localization of vitiligo patches and thus a patterned distribution in patients with nonsegmental vitiligo has remained poorly elucidated. A distributional similarity of the vitiligo patches with Blaschko's lines has been documented in patients with segmental vitiligo, both isolated segmental vitiligo and mixed vitiligo but never in cases of nonsegmental vitiligo.Methods: Distribution of nonsegmental vitiligo patches on face and neck regions was assessed and compared with Blaschko's lines and also with embryonic pigmentary segments on the face.Results: This study has documented distributional similarity of the nonsegmental vitiligo patches on face and neck with Blaschko's lines and the "embryonic pigmentary segments" among 154 (58.6%) cases. Patches around the palpebral and other fissures like periorbital, perinasal, perioral, and periaural were more common. In addition to the vitiligo patches, the spared areas were also found to respect the embryonic segmental outlines and follow the Blaschko's lines.Conclusion: Distributional pattern of the individual nonsegmental vitiligo patches along the Blaschko's lines and embryonic pigmentary segments suggests that mosaicism might control the susceptibility to the disease process in a patterned manner.Limitation: No genetic testing could be performed to confirm the hypothesis. Evaluation of nonsegmental vitiligo was done only on the face and neck areas. [ABSTRACT FROM AUTHOR]

The patched tumor suppressor gene (PTCH1) encodes a receptor, which is a key component of the hedgehog signalling pathway. Mutations in PTCH1 are implicated in the development of sporadic basal cell carcinomas (BCC), as well as those in Gorlin Syndrome. Rarely, BCCs may develop in a linear pattern along lines of Blaschko due to cutaneous mosaicism. In cases in which there are other features of Gorlin syndrome, genomic analysis has demonstrated lesional mutations in the Hedgehog signalling pathway. Causative mutations, however, have not been firmly demonstrated in the cases of linear and segmental BCCs in otherwise healthy individuals. Herein, we report a case of a 31 year‐old Caucasian woman with linear development of multiple superficial BCCs in a Blaschkoid distribution without other characteristic findings of Gorlin syndrome. Genomic analysis of lesional skin by whole‐exome sequencing identified a novel heterozygous mutation PTCH1: NM_000264.3, Exon 15, c.2336‐2337insGGTAGGA, p.Asp779Glufs*13 in PTCH1, shared by two discrete samples within the lesion, while no mutations were found in the non‐lesional skin or peripheral blood. Given the young age of our patient and linear distribution of BCCs on non‐sun exposed skin, our findings suggest segmental mosaicism. The patient was treated with topical 5% imiquimod with histologically confirmed clearance of BCCs in 2 months. [ABSTRACT FROM AUTHOR]

A boy with a 2‐year history of asymptomatic, linear pigmented macules involving the right side of the trunk and right upper limb. RCM revealed the dermal papillary rings were destroyed, and numerous irregular particulate structures with high refractive values were distributed in the superficial dermis. The RCM features implied the possibility of interface dermatitis. RCM was a complementary diagnostic tool for linear pigmented macules. [ABSTRACT FROM AUTHOR]

Lichen nitidus and morphea are common diseases, but an associated localization of both lesions is rare. Here, we describe the first case of lesions distributed along Blaschko's lines. A 24-year-old Japanese woman was referred to our clinic for evaluation of band-like plaques of 18-months history on the right lateral side of her abdomen. In addition, multiple milky-white papules were seen within the plaques. Histopathological examination showed there was sclerosis in the lower half of the dermis and well-circumscribed, dense, papillary dermal lymphohistiocytic aggregations showing a so-called "claw clutching a ball." Immunohistochemical analysis revealed that the morphea and lichen nitidus had similar characteristics. We speculated that unique immunologic events led to the development of lichen nitidus and morphea in our patient. [ABSTRACT FROM AUTHOR]

Pityriasis rosea (PR) is a common papulosquamous disorder that may be related to primary infection or endogenous reactivation of human herpesvirus 7 and 6. Based on morphology, distribution, and size of lesions, several atypical variants of PR have been described. PR following the lines of Blaschko represents an atypical variant that has seldom been described in the literature. Here, we describe a child with diabetes who developed PR in a symmetrical, blaschkolinear configuration. [ABSTRACT FROM AUTHOR]

Verrucous epidermal nevus is a common type of keratinocyte hamartoma present at birth or occurring later in life. Widespread multiple epidermal nevi (EN) may reflect genetic or chromosomal mosaicism. Blaschko has documented characteristic linear, zosteriform, unilateral or systematized patterns with streaks and swirls. They are resistant to treatment with the risk of recurrence. Giant congenital nevus unius lateralis (NUL) is known for its benign course with good supportive treatment however one particular case had a fatal neonatal outcome due to associated complications. Two interesting rare cases will be reviewed here.

Scleredema is an idiopathic condition with specific clincopathological findings, including symmetrical and diffuse nonpitting induration of the upper body and thickened dermis due to deposition of acid mucopolysaccharides. Here, we report a case of linear scleredema in a healthy female patient, who presented with firm induration of the skin over her right shoulder and arm in a Blaschkolinear distribution. The onset was insidious in childhood and stable over several years. While the clinical picture has closely mimicked linear morphea, the diagnosis of scleredema was confirmed by the typical histopathological findings. To the best of our knowledge, linear scleredema is a unique presentation that has not been previously reported. [ABSTRACT FROM AUTHOR]

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Herein, we report the case of a 12-year-old female who noted the recent onset of an oval, circumscribed, 10-cm papillomatous plaque affecting the thigh and vulva that showed histologic signs of lymphedema without evidence of secondary lymphedema. The sequencing of genes associated with a delayed onset of lymphedema or epidermal nevi (EN) - GATA2 and GJC2, and HRAS and KRAS, respectively - showed wild-type alleles. Polymerase chain reaction for human papillomavirus (HPV) DNA demonstrated infections with 15 HPV genotypes. Evidence of productive HPV infection, HPV capsid expression, and cytopathic changes was detected. At the 6-month follow-up, no evidence of recurrence was found after complete excision. The analysis of a consecutive series of 91 EN excision specimens revealed that 76% exhibited histologic evidence of lymphostasis. Notably, multiple acrochordon-like EN, which most closely resembled this case, showed similar signs of localized lymphedema. The late onset and evidence of lymphedema favors the diagnosis of congenital unisegmental lymphedema. However, the clinical findings and epidermal changes point to the diagnosis of EN. Moreover, localized verrucosis also accurately describes this patient's cutaneous findings. Based on the above evidence, we postulate that an abnormal development of lymphatics may play a primary role in the pathogenesis of some types of EN and facilitate productive HPV infection. © 2014 S. Karger AG, Basel

Background: The pattern of distribution of skin diseases remains one of the most elusive problems in dermatology, particularly when multiple pathologies are involved and coexistence of patterns is present. Most skin diseases show a predilection for certain body areas and are located in characteristic patterns. Many dermatoses exhibit lesions in a segmental fashion concomitantly with disseminated patterns. Sometimes the sites of predilection are inexplicable. Objectives: The main purpose of this paper is to give an overview on the peculiar arrangement of cutaneous lesions in both congenital and acquired skin disorders as well as reactive phenomena in vulnerable areas, in order to better recognise them clinically and understand their pathogenesis. Methods: Based on personal observations and a review of literature, this paper summarises the basics in understanding the patterned distribution of skin lesions, highlights the significance of the lines of Blaschko and their relationship with mosaicism, and describes some of the reactive skin phenomena. Results: Skin mosaicism plays a crucial role in the distribution and arrangement of skin lesions, as demonstrated by recent advances in genetic research in an increasing number of various skin diseases. [ABSTRACT FROM AUTHOR]

Verrucous epidermal nevus is a common type of keratinocyte hamartoma present at birth or occurring later in life. Widespread multiple epidermal nevi (EN) may reflect genetic or chromosomal mosaicism. Blaschko has documented characteristic linear, zosteriform, unilateral or systematized patterns with streaks and swirls. They are resistant to treatment with the risk of recurrence. Giant congenital nevus unius lateralis (NUL) is known for its benign course with good supportive treatment however one particular case had a fatal neonatal outcome due to associated complications. Two interesting rare cases will be reviewed here. [ABSTRACT FROM AUTHOR]

Hypopigmented skin lesions are frequent motive for consultation in the childhood. Several dermatological diseases are expressed by macules of whitish coloration and the lichen striatus is one of them; it is an autolimited, inflammatory and acquired dermatosis that has benign course and unknown etiology. The histological image is considered few specific; it is necessary to carry out clinical and histological approach. A case of a 9-year-old schoolgirl who presented papulous and pruriginous lesions with whitish coloration in the shape of linear plaques, located in the left hemithorax and left forearm is presented. Rev.cienc.biomed. 2013;4(2):335-338

Linear atrophoderma of Moulin (LAM) is a rare dermatosis in childhood and early adolescence. The exact etiology of LAM is still obscure. Several treatment modalities were reported but none was consistently successful. We report a case of LAM in which a favorable outcome was obtained with topical calcipotriol. The relevant literature is also reviewed.

Background: Nevi are proposed to reflect the mosaicism and thus generally follow the different archetypal patterns of mosaicism. Blaschko′s lines are the most common pattern of mosaicism. There have been many attempts to elucidate the Blaschko′s lines on face from the distributional patterns of different nevi, but studies that evaluated exclusively pigmentary nevi are sparse. Aims: This study attempted to evaluate the patterns followed by different pigmentary nevi on face and utilized this to elucidate the pattern of embryological pigmentation on face. Materials and Methods: Spatial parameters like shape, orientation, and distribution patterns of different flat pigmentary nevi on face were analyzed and graphically drawn on human facial diagram. This was compared with existing facial Blaschko′s lines. All cases of palpable pigmented nevi like congenital and giant melanocytic nevi and nevus spilus were excluded. Results: A total of 68 cases of pigmentary nevi on face (male-39, female-29) were examined. The shape and distribution lines were found to have a close similarity with Blaschko′s lines on face with distinct differences. Conclusions: The concept of facial embryonic pigmentary ′segment′, ′unit′ and existence of separate Blaschko′s lines for facial pigmentary nevi is conceived. Some insight into the pathogenesis of Blaschko′s lines is also proposed in this study.

Porokeratotic eccrine ostial and dermal duct nevus (PEODDN) is a rare nevoid condition characterized by asymptomatic grouped keratotic papules and plaques with a linear pattern on the extremities, having distinct porokeratotic histopathological features. The lesions usually present at birth or in childhood. We present here a case of late-onset PEODDN in a 23-year-old man who had lesions on the palm, forearm, arm and the chest along the lines of Blaschko, strictly localized to the left side of the body.

Incontinentia pigmenti is a rare, multisystem X-linked dominant genetic disorder caused by mutations in IKBKG, the encoding inhibitor of kappa light polypeptide gene enhancer in B-cells. Almost 80% of all cases result from a recurrent intragenic deletion mutation that removes exon 4-10. At present, this mutation can be detected by a multi-primer polymerase chain reaction ( PCR) technique although current protocols may preferentially amplify the wild-type allele and miss the deletion. Here, we report a female infant with incontinentia pigmenti that also affected her mother and sister, and two spontaneously aborted male siblings. We developed a modified PCR amplification method that provides more robust detection of the exon 4-10 deletion mutation, which was demonstrated in all affected females in this pedigree. [ABSTRACT FROM AUTHOR]

Verrucous epidermal nevus (VEN) is a common type of keratinocyte hamartoma present at birth or occurring later in life. It is seen at any site, but is less common on the head and neck, rarely seen on the face and very rarely involves the oral mucosa. Widespread multiple epidermal nevi may reflect genetic or chromosomal mosaicism. Blaschko has documented characteristic linear, zosteriform, unilateral or systematized patterns with streaks and swirls. They are resistant to treatment with risk of recurrence. A case of male child is presented here with extensive VEN with involvement of ear lobe and scalp of left side with cicatricial alopecia. Patient had delayed milestone development without any systemic involvement. [ABSTRACT FROM AUTHOR]

Porokeratotic eccrine ostial and dermal duct nevus (PEODDN) is a rare benign cutaneous disorder. It has clinical resemblance with comedo nevus, usually presents in palms and soles. The disease is characterized histologically by well-formed cornoid lamellae occurring in close association with or overlying dilated eccrine ducts and acrosyringia. The lesions follow the Blaschko's lines and may be systematized. We describe a 20-year-old female with PEODDN [ABSTRACT FROM AUTHOR]

Herein, we report the case of a 12-year-old female who noted the recent onset of an oval, circumscribed, 10-cm papillomatous plaque affecting the thigh and vulva that showed histologic signs of lymphedema without evidence of secondary lymphedema. The sequencing of genes associated with a delayed onset of lymphedema or epidermal nevi (EN) - GATA2 and GJC2, and HRAS and KRAS, respectively - showed wild-type alleles. Polymerase chain reaction for human papillomavirus (HPV) DNA demonstrated infections with 15 HPV genotypes. Evidence of productive HPV infection, HPV capsid expression, and cytopathic changes was detected. At the 6-month follow-up, no evidence of recurrence was found after complete excision. The analysis of a consecutive series of 91 EN excision specimens revealed that 76% exhibited histologic evidence of lymphostasis. Notably, multiple acrochordon-like EN, which most closely resembled this case, showed similar signs of localized lymphedema. The late onset and evidence of lymphedema favors the diagnosis of congenital unisegmental lymphedema. However, the clinical findings and epidermal changes point to the diagnosis of EN. Moreover, localized verrucosis also accurately describes this patient's cutaneous findings. Based on the above evidence, we postulate that an abnormal development of lymphatics may play a primary role in the pathogenesis of some types of EN and facilitate productive HPV infection. © 2014 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: Linear atrophoderma of Moulin (LAM) is a rare clinical entity which was first described by Moulin et al. in 1992. The diagnosis is clinical, characterized by acquired unilateral hyperpigmented, depressed band-like skin lesions following Blaschko's lines. The disease typically affects children or adolescents and has a good prognosis without evidence of long-term progression. To date, the pathophysiology is unclear. Different authors hypothesize that the disease is secondary to a mosaic manifestation as a result of a post-zygotic mutational event. Observations: Four patients (2 men, 2 women) had a history of unilateral band-like skin lesions located on the lower legs (50%) or the trunk (50%). Physical examination showed atrophic and hyperpigmented skin lesions along Blaschko's lines, which appeared during childhood in 3 cases and at the age of 20 in the last case. Lesions had progressed rapidly but seemed to have stabilized so far except for 1 case who presented spontaneous improvement. Histopathological examination revealed a normal epidermis with a hyperpigmented basal layer and a perivascular lymphocytic infiltrate in the dermis. Conclusion: LAM is a rare disease with 32 reported cases and remains an exclusion diagnosis. Since the problem is mainly esthetic, treatments should not be too aggressive. © 2013 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: Nevi are proposed to reflect the mosaicism and thus generally follow the different archetypal patterns of mosaicism. Blaschko's lines are the most common pattern of mosaicism. There have been many attempts to elucidate the Blaschko's lines on face from the distributional patterns of different nevi, but studies that evaluated exclusively pigmentary nevi are sparse. Aims: This study attempted to evaluate the patterns followed by different pigmentary nevi on face and utilized this to elucidate the pattern of embryological pigmentation on face. Materials and Methods: Spatial parameters like shape, orientation, and distribution patterns of different flat pigmentary nevi on face were analyzed and graphically drawn on human facial diagram. This was compared with existing facial Blaschko's lines. All cases of palpable pigmented nevi like congenital and giant melanocytic nevi and nevus spilus were excluded. Results: A total of 68 cases of pigmentary nevi on face (male-39, female-29) were examined. The shape and distribution lines were found to have a close similarity with Blaschko's lines on face with distinct differences. Conclusions: The concept of facial embryonic pigmentary 'segment', 'unit' and existence of separate Blaschko's lines for facial pigmentary nevi is conceived. Some insight into the pathogenesis of Blaschko's lines is also proposed in this study. [ABSTRACT FROM AUTHOR]