Max Joseph space is related to -

Ans. is 'c' i.e., Lichen planus Histological feature of lichen planusThe earliest finding is an increase in epidermal Langerhans' cells, associated with a superficial perivascular infiltrate of lymphocytes and histiocytes, impinging on the dermal-epidermal junction (DEJ).Mild spongiosis is followed by vacuolar alteration and clefting along the DEJ, with accumulation of necrotic keratinocytes (colloid bodies).Irregular acanthosis of the epidermis, irregular thickening of the granular layer, and compact hyperkeratosis.A focal increase in thickness of the granular layer and infiltrate corresponds to the presence of Wickham's striae. Degenerating basal epidermal cells are transformed into colloid bodies (15-20 im diameter)The rete ridges may appear flattened or effaced ('saw-tooth' appearance), and focal separation from the dermis may lead to max Joseph spaces.In ' active ' L P, a band-like infiltrate of lymphocytes and histiocytes, rarely admixed with plasma cells obliterates the DEJ.Epidermal melanocytes are absent or considerably decreased in number, while pigmentary incontinence with dermal melanophages is characteristic.