This chapter aims to equip with images of mastocytosis, plasma cell infiltrates, langerhans cell histiocytosis, xanthomatous infiltrates and eosinophilic infiltrates. Specific mast cell marker is CD117 but neoplastic mast cells are positive for CD2 or CD25. A specific marker for Langerhans cells is CD207. Cutaneous xanthomas do not show other inflammatory cells as against xanthogranulomas. Also, xanthogranulomas frequently show Touton giant cell but not foreign body giant cells. Flame figures seen in eosinophilic infiltrates are eosinophil granule major basic protein coated on normal collagen.