Acta Pathol. Jpn. 35(1) : 193-198, 1985

MOLLUSCUM CONTAGIOSUM OCCURRING IN AN EPIDERMAL CYST ON THE EYELID

Light and Electron-microscopic Studies with Literature Review

Yoshito UEYAMA, Yoshiyuki OSAYURA, Kmuo SHIMAMURA, Masaki NISHIMURA*, Satoru MACHIDA**,

and Norikazu TAMAOKI

Department of Pathology, School of Medicine, Tokai University, lsehara 'Department of Plastic Surgery, School of Medicine, Tokai University **Department of Dermatology, School of Medicine, Tokai Univmsity

We hereby report light and electron-microscopic (EM) studies on an unusual case of molluscum contagiosum occurring in an epidermal cyst. It was considered that the pre-existing cyst was inoculated with molluscum contagiosum viruses, which were confirmed electron-microscopically. We also would like to re-emphasize the usefulness of formalin fixed tissue for EM confirmation of viruses. ACTA PATHOL. JPN. 35 : 193-198, 1985.

Molluscum contagiosum is an infectious disease caused by DNA virus which is related to Pox group. The disease is widely distributed in the world, usually affecting children and young adults. Lesions usually occur on the face, arms, legs, genitals, back, and buttock^.^ However, the occurrence of molluscum in epidermal cyst has been reported to be rare.2

This short report deals with histological studies including electron-microscopy on an unusual case of molluscum contagiosum infecting a pre-existing epidermal cyst.

Case Report C l i n k 1 history.

An 11-year-old Japanese girl noted a white nodule on the left lower eyelid on July, 1981. The nodule of the lesion began to grow in October, 1981 and the redness around the lesion was also observed. The lesion reached a size of 1 x 2 cm on 26th, October, 1981.

On physical examination, a protruded skin of the left lower eyelid showed a white, slightly transluscent and well circumscribed nodule. Inflammatory sign around the lesion was also seen. The lesion was covered with the skin and no apparent connec- tion between the inner content of the nodule and skin surface was observed.

Accepted for publication March 10, 1984. kcLI %A, EM %2, a%, f i M EM, ttl1-B a, %- Mailing address : University, Bohseidai, Isehare, Kanagawa-Ken, 259-11, JAPAN.

Yoshito UEYAMA, Department of Pathology, School of Medicine, Tokai

MOLLlWl1M CONTAOIOSUM IN EPIDERMAL CYST Acta Pathol. Jpn.

Fig. 1. A scanning view of the molluscum contagiosum in the epidermal cyst. H.E. x5.

Fig. 2. High power view of Fig. 1. Right side of the picture shows the infected region and left side shows non-infected region. H.E. ~ 6 0 .

High power view of Fig. 2. showing molluscum bodies. H.E. x150.

Fig. 3.

35(1): 1985 Y. UEYAMA el ul. 195

Fig. 4. EM x 18,000. Fig. 5. Molluscum viruses. The size of the viruses ranged between 230-310 nm. The nucleus

Ultra-high power view of the lesion by EM, showing molluscum viruses.

is surrounded by electron dense amorphous coat, about 70-100 nm in thickness. EM ~ 4 6 , 8 0 0 .

MOLLUSCUM CONTAQIOSUM IN EPIDERMAL CYST Acta Pathol. Jpn. I96

She had no history of trauma to the area or previous skin disorders. No other molluscum contagiosum-like lesions were observed throughout the skin.

The lesion was clinically diagnosed as an epidermal cyst and excisional biopsy was performed. The specimen was fixed in 10% formaldehyde solution, embedded in paraffin and stained with hematoxylin-eosin (H.E.).

For EM examination, the tissue initially fixed in 10% formaldehyde, was refixed in 2% glutaraldehyde, post-fixed in 2% osmic acid and embedded in Epon.

At present, the lesion shows no recurrence.

Pathological Studies Light microscopic features : The scanning view of the skin lesion showed a subepider- ma1 cyst containing lamellated horny materials and desquamated, enlarged squamous cells with glassy, eosinophilic materials in the cytoplasm (Fig. 1). The cyst was surrounded by intense inflammatory infiltrates of lymphocytes, neutrophils, and eosinophils. In Figure 2, the right side of cyst wall shows infected epidermis contain- ing ground glass material in the cytoplasm, which is consistent with molluscum bodies. The left side of the cyst wall showed non-infected areas of the squamous epithelium.

Figure 3 shows a high power view of this molluscum bodies, characterized by glassy amorphous materials in the cytoplasm.

Electron-microscopic features : The infected cells contained intracytoplasmic inclu- sion bodies consisting of numerous molluscum viruses (Fig. 4). The nucleus of the cell has been displaced to the periphery of the cell. Tonofibrills were seen among the viruses (Fig. 4).

High power view of the molluscum viruses showed dumbell-shaped nucleoids surrounded by capsids (Fig. 5 ) . The size ranged between 230-310 nm. The nucleus was surrounded by electron dense amorphous coat, about 70-100 nm in thickness.

Table 1. Summary of PreviouS and Present Cases of Molluscum Contagburn Occurring in Epidermal Cyst

Other Duration Inflam- mation Size molluscum Sex Age Site

Hodge’s male 33 Y left - 2 + 7 M

Fellner’s female 28 Y eyelid - 3 mm - 2M

Hendrick’s female 15 M scalp + 4 mm 2 4 M

Sakai’s female 7 Y abdominal 2 2 x 3 mm - 2 M

our case female 11 Y eyelid + 1 x 2 cm - 4 M

case thigh

case

case

case skin

35(1): 1985 Y. UEYAMA el ~ l . 197

Comments

Light microscopically, the ground glass apppearance was thought to be typical for molluscum contagiosum. Electron microscopically, the morphology of viruses were also typical for molluscum contagiosum viruses. Although the tissue was initially fixed in 10% formaldehyde solution, ultrastructual preservation was statisfactory. This may also indicate the usefulness of formaldehyde fixed tissue for EM confirmation of viruses.

In our case, the presence of intact squamous epithelium in the cystic lining may indicate the molluscum infection to the pre-existing epidermal cyst. However, the route of the infection of the molluscum viruses was not ascertained, because no apparent disclosure or eruption of the epidermal cyst to the surface was observed in our case.

From the literature review, we were able to find only 4 previous rep or ti^^^^.^.^ of molluscum contagiosum occurring unequivocally in an epidermal cyst. There seems to be many other cases which were not reported in the literature, because some cases are shortly cited in the abstract of the meeting of academic societies. However, we could not confirm any abstract concerning molluscum contagiosum occurring in the epidermal cyst.

Characteristics of the previous cases and our case are summarized in Table 1. KANAMURA’S case4 may be one of the cases, but we cannot confirm them as molluscum contagiosum occurring in the epidermal cyst, because the entire wall is infected with molluscum viruses and there was no evidence of pre-existing epidermal cyst. There- fore, KANAMURA’S cases are excluded from Table 1.

Although it may be difficult to summarize the general characteristics from these small number of cases, all patients, were female except for HODGE’S case. The lesions were located in the thigh, scalp, eyelid, and abdominal skin. The sizes of the lesions were 3-4 mm except for our case (1-2 cm). The degree of inflammation was variable. Other molluscum lesions were found only in HODGE’S case. The duration of the disease was from 2 to 7 months.

Molluscum contagiosum occurring in the epidermal cyst has been considered as a rare complication, partly due to lack of detailed histologic examination and partly due to difficulty in showing co-existence of epidermal cyst and molluscum bodies. When the entire cystic wall is infected with molluscum viruses, differential diagnosis between simple molluscum contagiosum growing downwards and molluscum contagiosum in an epidermal cyst, may be difficult. As shown by our experience, the diagnosis could be confirmed only by the existence of the non-infected wall of the epidermal cyst.

Closer histologic examination might enable one to diagnose more cases of such an unusual association.

Acknowledgement : electron-microscopic photographs.

The authors wish to thank Mr. Takeshi KAWAKAMI for his technical assistance in

198 MOLLUSCIJM CONTAQIOSUM IN EPIDERMAL CYST Acta Pathol. Jpn.

References 1. FELLNER, M.J. and OSOWSKY, M.J.: Molluscum contsgiosum in an epidermal inclusion

cysts on the eyelid. Int. J . Dermatol. 18 : 160-161, 1979. 2. HENDRICKS, W.M., MYERS, D.E., and CHUNC Hong Hu : Molluscum contagiosum occurring

in an epidermal inclusion cyst. Cutis. 26 : 180-184, 1980. 3. HODQE, S.J., FLIECELMAN, M.T., SCHRODT, G.R., and OWEN, L.G. : Molluscum contagiosum

occurring in epidermal inclusion cystg. Arch. Dermatol. 108 : 257-258, 1973. 4. KANAMARU, R. : Molluscum contagiosum-misdiagnosed cases. Hifubyo Shinryo. 2 :

5. Molluscum contagiosum, In Rhodes and Van Rooyen, (Editors) : Textbook of Virology, 5th edition, p. 346-348, 1968.

6. SAKAI, S., Dox M., and TAMAI, S. : Two cases of molluscum contagiosum. Hifu Shinryo.

585-587,igao.

21 : 1057-1059. 1979.