European Journal of Cardiovascular Medicine

Vesiculobullous disorders (VBD) represent a heterogeneous group of dermatoses in which the primary lesion is a vesicle or a bulla on the skin or mucous membrane or both. Vesicles and bullae are fluid filled lesions distinguished on the basis of size; vesicles are <5 mm while bullae are >5 mm.  There are wide variety of vesiculobullous disorders, some of which can be extremely debilitating and even fatal ⁽¹⁾. Various pathologic processes can lead to development of vesiculobullous lesions which include inflammatory, infective, autoimmune, drug induced and genetic ⁽²⁾. Very often, these diseases cannot be differentiated clinically and hence requires histopathological examination of skin punch biopsy for diagnosis. Biopsy is the gold standard for diagnosis of vesiculobullous lesions. They also provide added information regarding the pathogenic mechanisms behind these lesions ⁽³⁾. Histopathological evaluation of these disorders includes identification of blister separation plane, presence or absence of inflammatory cells and predominant type of inflammatory cells in the blister ⁽⁴⁾.

Direct Immunofluorescence (DIF) studies and Electron Microscopy assist in the diagnosis of cases where histopathology is not conclusive ⁽⁵⁾. Only few specialized centres offer these and cost of these tests is quite high  compared to routine histopathology. Therefore reliability of histopathology in correlation with clinical findings in diagnosing bullous disorders is an area that needs to be evaluated. The objectives of this research are to study the histopathological spectrum of vesiculobullous disorders and to document the role of clinical and histopathological correlation in diagnosing various bullous disorders of skin.

This is a descriptive study conducted in Department of Pathology, Government Siddhartha medical college, Vijayawada, Andhra Pradesh,  India for  three years period between March 2021-February 2024.Forty nine (49)  skin biopsy specimens of patients  presenting with vesiculobullous lesions in the outpatient department  and  inpatient department during the study period were included in the study. Informed consent was taken from the patients. Vesiculobullous lesions due to thermal and traumatic causes were excluded. Detailed history regarding age, gender, presenting complaints and history of drug reaction,  distribution and morphology of  blisters were recorded. Skin biopsy specimens which were received in 10% formalin solution are fixed overnight and paraffin embedded. 4-5 μm thin sections were taken, stained with haematoxylin & eosin stain and examined under  light  microscope. Histopathological findings evaluated are the level of split, content of the blister, predominant type of inflammatory cell present in the blister, associated epidermal and dermal changes

During the study period a total of 745 skin biopsy specimens were received out of which 49 were vesiculobullous lesions which constituted 6.6 % of skin biopsy specimen.  Male preponderance (30 cases; 61%) with male: female ratio of 1.57:1was noticed. Majority of patients presented between 50-70 years of age (22 cases; 45 %) with mean age of 49.1 years (Figure:1). The youngest was a 4 year-old male child diagnosed as Epidermolysis bullosa simplex (EBS)  and the oldest was 78 years old female  with a diagnosis of Pemphigus vulgaris (PV) on histopathology. Extremities were found to be the most common  site of involvement  constituting  30 cases (61%) with lower limbs (18 cases; 37%)  , upper limbs (12 cases;  24%)  followed by  trunk (10 cases; 20%),  face (2 cases, 4%) and scalp (1 case, 2%).

Bullous pemphigoid (BP) (14 cases; 28.6 %) and Pemphigus vulgaris (13 cases; 26.5%) were the most frequently diagnosed cases in this study (Table -1) which are followed by pemphigus foliaceous (5 cases; 10%) . BP was most frequently encountered in 7^th decade of life (5 cases; 10%) followed by 5^th decade (4 cases; 8%).  In the present study 24 cases (49% ) showed  subepidermal bullae (Table -2), 13 cases  (27%) showed  suprabasal bullae ,  and  subcorneal  in 6 cases(12%).  No bullae were found in 5 cases (10%) . Predominant inflammatory cells that are identified  in blister are  eosinophils in 12 cases (25%) followed by neutrophils in 10 cases (20%).  Acantholytic cells were seen  only in 3 cases (6%) . Patchy dermal mild to moderate  perivascular lymphocytic infiltrates  were seen in almost all cases. Concordance between clinical and histopathological diagnosis was observed in 44 cases (89%). Discrepancy between clinical diagnosis and histopathological diagnosis was encountered in 5 cases (10%) for which direct immunofluorescence study was advised.

Figure: 1 Age wise distribution of vesiculobullous lesions of skin

Figure -2: Bullous pemphigoid showing tense bullae on the posterior aspect of trunk

Figure -3: Microscopic image of Sub-epidermal blister in Bullous pemphigoid

Figure -4: Flaccid bullae over thigh in Pemphigus vulgaris

Figure -5: Microscopic image of Supra-basal blister with tombstone appearance in Pemphigus vulgaris

Table :1 Distribution of Vesiculobullous lesions of skin

Table :2 Plane of bullae in vesiculobullous lesions of skin

Skin is the single largest organ of the body, both in weight and surface area. It provides protection against a wide variety of external threats, including mechanical, water loss, biological, ultraviolet light and chemical. Vesicles, bullae may occur in various skin disorders but they differ in their etiology, pathogenesis, severity and clinical course. Clinically, all the patients with vesiculobullous diseases may not present with classical morphology and distribution of the lesions. But, most of these disorders have characteristic histopathological findings like blister separation plane, the mechanism of blister formation and the character of the inflammatory infiltrate, including its presence or absence, its pattern, and the specific cell types involved. Hence accurate diagnosis of these diseases can be achieved by correlating clinical features with histopathological findings.

In the present study males out numbered females. Out of the 49 patients, 30 were males (61%) and 19 were female (39%) with male to female ratio of 1.57:1. Our study was in concordance with the studies by Khan et al ⁽⁶⁾, Murthy et al ⁽⁷⁾ while studies by Deepthi et al ⁽⁸⁾ and Pavani et al ⁽⁹⁾, showed female preponderance. Majority of patients presented between 50-70 years of age (22 cases; 45 %) with mean age of 49.1 years which was similar to various Indian studies but was slightly different from the western studies where the mean age of presentation was higher. Extremities were found to be the most common  site of involvement  constituting  30 cases (61%) with lower limbs (18 cases; 37%)  , upper limb (12 cases;  24%)  followed by  trunk (10 cases; 20%). Similar findings were observed by Anupama et al ⁽¹⁰⁾ and Mittal H et al ⁽¹¹⁾. Oral cavity involvement was seen in all the cases of pemphigus vulgaris . Nikolsky’s sign was positive in all the cases of PV. In the present study 24 cases (49% ) showed  subepidermal bullae , 13 cases  (27%) showed  suprabasal bullae ,  and  subcorneal  in 6 cases (12%) (Table -2). Predominant inflammatory cells that are identified  in blister are eosinophils in  25% of cases  which is in correlation with study done by Mittal H et al⁽¹¹⁾. Neutrophilic infiltrate was predominant  in other studies ^{(10, 14)}.

Bullous pemphigoid (BP) (14 cases; 28.6 %) and Pemphigus vulgaris (13 cases; 26.5%) were the most frequently diagnosed cases in this study (Table -1) which are followed by pemphigus foliaceous (5 cases; 10%) Similar findings were observed in studies by Thejasvi et al where Bullous pemphigoid was the predominant lesion ⁽¹²⁾. BP is an autoimmune pruritic skin disease that preferentially effects elderly people with autoantibodies directed to components of the basement membrane, particularly the BP antigens BP180 and BP230⁽¹³⁾. The disease is clinically characterized at an early stage by urticarial rash, but could also appear as dermatotic, targetoid, lichenoid, nodular or even without visible rash (essential pruritus). Tense bullae eventually erupt (Figure-2). Any part of the skin surface can be involved with rare mucosa involvement. On Histopathological examination, BP  is characterized by subepidermal bullae with eosinophils and superficial dermal oedema (Figure-3). Similar histopathological findings were noticed in our study in all cases of BP. Clinical presentation along with histopathology is usually sufficient for definitive diagnosis of BP ⁽¹³⁾. In our study, almost all cases of BP showed complete correlation between clinical and histopathological diagnosis. Cases of BP, Linear IgA dermatoses, Epidermolysis Bullosa Acquisita ( EBA) show sub epithelial plane of separation. Direct immunofluorescence (DIF) is essential in such cases in making accurate diagnosis for proper patient management. The gold standard for diagnosis of EBA vs BP is the identification of immune deposits on the dermal side ('floor') for EBA and on epidermal side (roof) for BP.

Pemphigus vulgaris, comprising 26.5% of the cases in present study is an autoimmune blistering disease that comprises the most common type of Pemphigus. Autoantibodies targeting Desmoglein (Dsg) adhesion proteins are found in this disease. The age range of this disease is wide with predominance between 40–50 years (43% of cases) and being more common in males (16% ) in present study. Patients present with  painful ulcers, erosions and blisters on skin and mucous membranes (Figure-4). On histopathology examination  PV is characterized in its early stage by intercellular oedema with loss of intercellular attachments. The fully developed disease shows suprabasal clefting with intact basal cells on basement membrane giving the lesion a tomb stone appearance (Figure-5). The cleft shows occasional acantholytic cells along with mixed inflammatory cells. In our study,  neutrophilic infiltrate was noticed. PV with its distinct histological picture can easily be diagnosed on histopathology alone.

The other relatively less frequent number of diseases included in our study were  Pemphigus foliaceous (5 cases; 10%) , Steven Johnson syndrome (3 cases 6.2%)  and 3 cases (6.2%) of Bullous SLE. Remaining less frequent entities are listed in Table-1.Out of 49 cases, percent agreement between clinical and histopathological diagnosis is 89.8 %. A previous study by Karattuthazhathu AR et al ⁽¹⁾ and Gupta S et al ⁽¹⁵⁾ showed 87% and 90%  correlation among clinical and histopathological diagnosis respectively.  While another study by Murthy TK et al ⁽⁷⁾ showed 64.88% concordance. In present study 5 cases (10.2%) showed discordance between clinical diagnosis and histopathological findings for which DIF studies were advised.

Vesicobullous disorders represent a heterogeneous group of dermatoses with variable clinical manifestations and cause significant morbidity and mortality to the patient if not diagnosed and treated appropriately. Histopathological evaluation of skin punch biopsy is a cost effective, widely available and reliable diagnostic modality in association with clinical correlation. Present study showed approximately 90% concordance between clinical and histopathological diagnosis in Vesicobullous disorders of skin. DIF is helpful in cases where there is discrepancy between clinical and histopathological features. DIF is only a supplement but not a substitute in diagnosis of VBD. In low resource settings like ours where patients of  low socioeconomic strata  are majority, clinical diagnosis and histopathology forms the cornerstone in arriving at the diagnosis.

Conflict of Interest

None

Funding Support: Nil

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