Pictorial case studies: Four presentations of skin conditions

Diagnosis, differential diagnosis and management of four cases. By Dr Brian Malcolm

Figure 1: Cutaneous B-cell lymphoma (Photograph: Dr Brian Malcolm)

Cutaneous B-cell lymphoma

This 83-year-old woman was urgently referred by her GP because of a rapidly developing, but asymptomatic, diffuse infiltrative eruption involving her left ankle. This had developed over a short number of weeks.

Cutaneous B-cell lymphoma

Clinical features, differential diagnosis and management
Clinically, lymphoma was suspected, although a differential diagnosis would include a number of inflammatory dermatoses and cutaneous sarcoidosis.
GPs need to be aware of this condition, given the ageing demographic; I saw a virtually identical presentation on the lower leg of an 85-year-old man a week after this case.
The diagnosis should not be missed, however, if the important rule is followed of always carrying out a biopsy on so-called ‘EFG’ lesions (elevated, fixed or firm and growing).
Histology is key and unless they are already in the care of a very specialised dermatology unit, such patients are referred for further investigation and management by regional specialist multidisciplinary teams, with oncological and haematological input. This differs from the more common T-cell lymphomas, which, unless advanced, largely remain within the remit of the dermatology department.
Primary B-cell lymphomas comprise 20-25% of all cutaneous lymphomas and generally have a good prognosis. There is a subset, however, occurring on the lower limbs of elderly women, which can behave more aggressively and carry a risk of disseminating to extracutaneous sites.

Figure 2: Giant porokeratosis (Photograph: Dr Brian Malcolm)

Giant porokeratosis

This 68-year-old male patient presented with a single, isolated, gradually evolving, well-marginated lesion on his lower leg. This had been present for about 18 months and was essentially causing him no symptoms.

Giant porokeratosis

Clinical features, differential diagnosis and management
The term ‘porokeratosis’ covers a number of different lesion types sharing a characteristic marginal scale, described as a cornoid lamella.
Histologically, this represents a column of parakeratotic keratinocytes. It is not unique to porokeratoses, being also described in viral warts and various ichthyotic disorders.
The most common presentation is disseminated superficial porokeratoses occurring multiply on the limbs of fair-skinned middle-aged patients. There is also a rare childhood variant that demonstrates autosomal dominant inheritance.
The term ‘porokeratosis of Mibelli’ should be reserved for single or scanty larger lesions. Diverse sites may be involved, such as the face, cornea, mucosal surfaces and genitalia.
Giant porokeratosis, defined as >20cm diameter, is much rarer and most often involves the foot. There remains debate as to the malignant potential of porokeratoses, but the giant variety is believed to have the highest potential for such change.
Effective therapy for all types of the condition remains elusive. Treatments such as 5% fluorouracil, cryotherapy, topical and systemic retinoids, calcipotriol and photodynamic therapy have all been tried, with varying degrees of success.

Figure 3: Chronic superficial scaly dermatosis (Photographs: Dr Brian Malcolm)

Chronic superficial scaly dermatosis

This otherwise fit 52-year-old patient had gradually developed a mildly scaly, non-itchy eruption over his trunk and limbs for some 20 years. He was on no medications and had no family history of skin problems.

Chronic superficial scaly dermatosis (also known as digitate dermatosis), parapsoriasis-en-plaques

Clinical features, differential diagnosis and management
As the nomenclature suggests, this is a very persistent condition of unknown cause, characterised by well-demarcated, finger-like eczematous patches or plaques with a subtle surface scale. Other areas can be arcuate, curvilinear and oval in shape.
The condition is considered benign, but occasionally, such presentations can evolve into T-cell lymphomas and if there is clinical suspicion, serial biopsies plus PCR and immunological studies should be given consideration.
Most cases develop in middle age, more commonly in men, characteristically affecting the limbs and trunk and sparing the face and extremities. Mild topical steroids and phototherapy are options if treatment is indicated.

Figure 4: Idiopathic guttate hypomelanosis (Photograph: Dr Brian Malcolm)

Idiopathic guttate hypomelanosis

In a period of about two years, this 53-year-old patient developed scattered areas of hypopigmentation over her forearms and the dorsal surfaces of her hands. She was otherwise well and asymptomatic, and had no history of autoimmune disorders.

Idiopathic guttate hypomelanosis

Clinical features, differential diagnosis and management
This is a more florid example of what is quite a common condition, classically affecting the exposed limbs of white women. The morphology is of a number of well-demarcated, porcelain white, irregularly shaped macules 2-6cm in size.
It can, however, occur in unexposed sites in black skin. It is commonly mistaken for vitiligo, but there is often the presence of a subtle scale.
Histological analysis reveals a reduction in melanocytes and a lack of mature melanosomes. No reliable treatments are available, although cosmetic camouflage is an option and sun protection is important. n
  • Dr Brian Malcolm is an associate specialist and GPSI in dermatology in Barnstaple, Devon, honorary associate lecturer, Cardiff University, and committee member of the Primary Care Dermatology Society

Competing interests: None declared

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